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Symptoms of a Bad EGR Valve

Dan Ferrell writes about do-it-yourself car maintenance and repair. He has certifications in automation and control technology.

Has your EGR valve (your Exhaust Gas Recirculation valve) gone bad? Maybe. I'll tell you the symptoms below. But before you start replacing parts, keep in mind that the same engine performance problems that indicate a bad EGR valve can also indicate problems in other parts of the system. If you don’t do your troubleshooting, you may end up replacing parts unnecessarily and wasting time and money.

This article will tell you several things:

  • the symptoms of a bad EGR valve;
  • how to start investigating whether the problem is your EGR valve or something else;
  • what the EGR valve does and how it works;
  • and the different types of EGR valves.
EGR valve passages plugged with carbon deposits.

EGR valve passages plugged with carbon deposits.

Symptoms of a Bad EGR Valve

Symptoms of a bad EGR valve include:

  • rough idling or stalling
  • a smell of fuel
  • increased fuel consumption
  • pinging, tapping, or knocking sounds
  • failed smog test
  • Check Engine Light on

Another symptom you may not see often is a misfire. The misfire is actually caused by clogged passages in the intake manifold.

Carbon buildup from exhaust gases flowing through the EGR valve may restrict flow to one or more cylinders. The rest of the cylinders then will get all the exhaust flow, leading to the misfire.

The intake ports and EGR valve itself may also have carbon deposits. All these passages and ports will need to be cleared.

Valve Stuck Open vs. Valve Stuck Shut

Actually there are two kinds of bad EGR valves, with different symptoms. An EGR valve can fail in two ways: It can be open all the time, or it can be closed all the time.

If the EGR Valve Sticks Open:

This will cause a continuous flow of exhaust gases into the intake manifold. You'll notice one or more of the following symptoms:

  • A rough idle upon starting the engine (that is, when the engine is cold) and sometimes at a stop light or while looking for a spot in a parking lot (that is, at low engine speeds in a warmed-up engine).
  • Stalling when the engine idles.
  • Increase in fuel consumption.
  • A slight—or strong—fuel odor while operating the vehicle, because of the increase in hydrocarbons leaving the tailpipe (see the next symptom).
  • Your car fails the emissions test. When the engine is running at low RPM, lower temperatures in the combustion chambers prevent all the fuel from burning, so the flow of unburned hydrocarbon gases coming out of the tailpipe increases significantly.
  • The Check Engine light (or Malfunction Indicator Light, MIL, depending on your model) illuminates on your dashboard.
  • You feel the engine has low power, especially at low speeds.

If the EGR Valve Sticks Closed:

This will permanently block the flow of exhaust gases into the intake manifold. You'll notice one or more of the following symptoms:

  • A pinging or tapping noise coming from the engine at low RPM (at speeds higher than idle). The noise is the sound of early ignition of the fuel when it meets high temperatures.
  • Loud detonations. A second ignition can happen after the normal ignition, and the two can combine with enough power to cause engine damage.
  • Your car fails the emission test. High temperatures in the combustion chamber allow the excessive formation of oxides of nitrogen, which are released through the tailpipe.
  • The Check Engine light, or Malfunction Indicator Light (MIL), illuminates on your dashboard.

Troubleshooting: Is It the EGR Valve or Something Else?

To make things even more complicated, the same engine performance problems that indicate a bad EGR valve can also indicate problems in other parts of the system:

  • spark plugs,
  • spark plug wires,
  • the fuel filter,
  • the fuel pump regulator,
  • and various engine sensors.

An increase in hydrocarbon emissions isn’t necessarily caused by a stuck-open EGR valve. Problems in other systems may cause this same symptom as well: a leaking fuel injector, bad ignition timing, bad cylinder compression, bad oxygen sensor, or other problems.

Similarly, an increase in NOx may be caused by a vacuum leak, a clogged fuel injector, low fuel pressure, a leaking head gasket, or other problems.

A rough idle may be caused by a faulty ignition coil, a vacuum leak, or an ignition system problem.

So before spending money and replacing parts, troubleshoot the EGR valve and other system components to try to narrow down the problem. This article, How to Test an EGR Valve, gives a series of troubleshooting procedures on vacuum and electrical vacuum-controlled EGR valves, and will help you find out if the problem is your EGR or something else.

If your car has an electronic EGR valve, troubleshooting will be easier, because it will have a Check Engine or MIL light on the dashboard, and you will be able to find out what engine system malfunction triggered the light. With an aftermarket scan tool, you can pull the trouble codes from the computer's memory and see what system or components are causing the problem. Then, you can try to find the fault with the help of the vehicle repair manual for your particular car make and model. Haynes makes good inexpensive aftermarket manuals.

Common DTCs Related to the EGR System or Valve

On some vehicle models, you'll see the check engine light (CEL) illuminate when there's a problem detected in the EGR system.

Check the EGR valve and, if necessary, the rest of the system, if you find one or more of the following diagnostic trouble codes (DTCs).

  • P0400: Exhaust gas recirculation (EGR) flow problem. Check the EGR valve, hose or electrical connections, as necessary.
  • P0401: Insufficient exhaust gas recirculation flow. Check the EGR valve and possibly clogged EGR ports or passages.
  • P0402: Excessive exhaust gas recirculation. Check for a stuck-open EGR valve, an electrical short in a related component or even a misrouted hose in the system.

The EGR's Job: Processing Exhaust Gases

The outside air picked up through the engine's intake manifold contains close to 80 percent nitrogen and 20 percent oxygen, along with small amounts of other elements. When outside air combines with the fuel and ignites in the combustion chamber, temperatures can reach above 2500o F (or 1370o C). Combustion at these temperatures burns the usually inert gas nitrogen, creating oxides of nitrogen (NOx) gases, which cause air pollution and human health problems.

However, when the burned exhaust gases are introduced back into the combustion chamber through the EGR valve, temperatures decrease, inhibiting the formation of NOx gases.

What the EGR Valve Does

The EGR valve is a small component designed to allow the flow of exhaust gases into the intake manifold in controlled amounts. As such, it's a simple valve that closes and opens as needed.

The EGR valve has one single job to do, regardless of the system configuration, type of control and number of sensors: that is, to either open and direct exhaust gases into the combustion chamber, or to close and keep them from entering.

Whenever you start the engine, the valve comes alive and waits in a closed position, blocking the flow of exhaust gases.

Once the engine reaches operating temperature and speed increases, the valve—either through vacuum or electronic control—gradually opens, allowing burned exhaust gases to enter and combine with the air-fuel mixture inside the combustion chamber. If you slow down sufficiently or come to a stop, the valve gradually closes and blocks the flow of exhaust gasses. And the process continues for as long as the engine is running.

After you shut off the engine, the EGR valve closes and remains in that position.

Types of EGR Systems

Gasoline and diesel-powered engines on the road today may use one of several different EGR valve configurations.

  • On older vehicle models, you'll recognize the EGR valve as a round, thick metal disc about three inches in diameter, usually towards the top of the engine and on the side. On these older models, a small-diameter vacuum hose operates a basic EGR valve. The hose connects the top of the valve to the throttle body or carburetor. The valve's metal disk houses a vacuum diaphragm, spring, and plunger.
  • Later models come equipped with electronic-vacuum EGR valves inside a small block or cylinder. The valve works the same way as in older models, except that an electronic EGR position sensor communicates with the car's computer for better control. You may see electric solenoids connected through vacuum lines to the valve as well.
  • Newer vehicle models use electronic EGR systems that may include additional components, even a digital valve that eliminates the need for vacuum control altogether.
  • A more radical design, implemented in a few models, was the replacement of the valve with EGR jets at the bottom of the intake manifold.
  • Some newer high-efficiency engines, for example those with variable valve timing (VVT), don't even use an EGR system.

Types of EGR Valves

  • Vacuum-controlled EGR valve
  • Back-pressure EGR valve
  • Electronic vacuum-controlled EGR valve
  • Digital EGR valve
  • EGR jet (in place of EGR valve)

Locating the EGR on a Corvette and on a Truck

A Sensor Related to the EGR on the Ford Focus

Bad EGR valve symptoms vary and resemble problems in other engine systems. But now that you know the type of symptoms a troubled EGR valve will produce, include it in your troubleshooting tests. And restrain yourself from swapping components trying to fix the problem before knowing which part is causing you trouble. Most of the time, you'll just spend time and money unnecessarily. Troubleshoot your EGR valve and other components.

Test Your Knowledge

For each question, choose the best answer. The answer key is below.

  1. Which condition does NOT point to a potentially failed EGR valve?
    • Excessive oxides of nitrogen
    • Excessive hydrocarbon
    • Excessive hydrocarbon and carbon monoxide
  2. Which of these is NOT a symptom of an EGR valve stuck open?
    • Rough idle and stalling
    • A smell of fuel
    • High oxides of nitrogen (NOX) results on emissions test
  3. Which of these is NOT a symptom of an EGR valve stuck closed?
    • Pinging or tapping
    • Loud detonations
    • High hydrocarbon (HC) results on emissions test
  4. What else, besides an EGR valve stuck open, can cause high hydrocarbon emissions?
    • Bad oxygen sensor
    • Warped rotors
    • Transmission fluid leak

Answer Key

  1. Excessive hydrocarbon and carbon monoxide
  2. High oxides of nitrogen (NOX) results on emissions test
  3. High hydrocarbon (HC) results on emissions test
  4. Bad oxygen sensor

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

Questions & Answers

Question: I have had my EGR valve cleaned and then replaced in my 2002 Ford Tauras which has 49,000 miles. Now it idles rough and the check engine light came back on. What could be the issue?

Answer: If the trouble codes point to the EGR, then there's possibly something wrong in the system. It depends on the codes. Make sure the circuits (wiring) are checked as well.

Question: I have a Hino 2011 268, and the SCR malfunction light turns on and off. What is wrong?

Answer: There could be an intermittent problem with the SCR system. You may be able to get the codes. This video may give you an idea of how to get the codes yourself:

https://www.youtube.com/watch?v=VLf3dgDlLoY.

Question: If I have a bad EGR valve, will it throw a code for a misfire in cylinder number 2?

Answer: A bad valve most likely will cause a random misfire since it doesn't direct exhaust gases to a particular cylinder. If you are getting a code for the number 2 cylinder, check the injector, spark, or fuel problems for that cylinder.

Question: Why would the EGR valve leak oil?

Answer: The oil may come through a seal from the actuator rod which somehow connects to the crankcase ventilation (CCV) system. This seems to be a recurrent problem on some models. You may try replacing the EGR valve and see if the problem doesn't return.

Question: My 98 Lexus ES300 has codes po001/po004, can the EGR set off those codes?

Answer: The description for these codes point to the electrical circuit that connects the fuel pressure regulator to the car computer.

Check first for proper connections and corrosion, a leak on the pressure regulator or failing pump.

If the fuel rail on your engine has a fuel shut-off, check that one too.

Question: I tapped my cars EGR valve when the engine was running and automatically it switched off. Later trying to start it, it produced a fuel odor and doesn't start. What could be the problem?

Answer: Probably tapping the valve didn’t affect the engine directly. If the diaphragm in the valve was already damaged probably. If the valve is stuck open, it can cause a rough idle, stall and increase fuel consumption (fuel odor you’re are able to smell during engine operation). This other post may help you test the valve:

https://hubpages.com/auto-repair/How-to-Test-an-EG...

Question: I am driving a Mazda 2 DE. And when I disassembled the EGR, it's filled with water flowing out. My EGR is not water cooled. Thus, there shouldn’t be water in there. Would this be a sign of leaking head gasket with coolant seeping into the cylinder area?

Answer: If there’s coolant, you may have a cracked head, gasket or block. But there could be other symptoms as well if this is the case. If you found water, this most likely is the steam you see coming out the exhaust (from fuel burning) when starting the engine, usually in cold temperature climates.

Question: I got my EGR valve changed. Now my car cabin smells of exhaust fumes when my heat is on. What would cause this?

Answer: Check the EGR valve gasket. Make sure it was replaced and put in place correctly. The valve should be properly installed. Or you may have an exhaust leak. The fumes are probably going from the engine compartment, ventilation system, and the cowl next to the windshield. You want to fix this as soon as possible. Carbon monoxide is highly poisoning.

Question: I just had the EGR valve and its controller replaced. I was hoping this would turn off the check engine light that goes on and off periodically. Not only did it not fix the check engine light, but now my car idles rough at stoplights and sometimes just at idle. My mechanic, when he replaced the EGR valve, said as I was leaving that it might take a little time for the valve and the idle to the light to become compatible? Do you know what he was talking about? Thank you.

Answer: I don’t know what exactly he means by “for the valve in the idle to the light compatible.” But, if he disconnected the battery while working on the EGR system, he might be referring to the car’s computer relearning its idle and fuel trim strategy, which usually gets erased when power is disconnected. It erases data from memory.

Also, do you know if he cleared any trouble codes from the computer memory after replacing the valve? If not, you can go to a local auto parts store and ask them to pull any trouble codes (so that you can verify the code relates to the EGR system) and have them clear the memory. This could help. Also, you can wait for the computer to relearn the strategy, which may take a few miles. Or you can check your vehicle repair manual and see if it gives you the procedure to perform the idle relearn process.

Question: I have a Crown Victoria that will not stay running unless my foot is on the gas, is it the EGR?

Answer: Check the idle air control (IAC) valve for proper operation or carbon buildup. You'll need to remove it and do a visual inspection of the valve, as well as the ports.

Question: I have a 2008 Ford Crown Victoria PI. When I press the throttle quickly, at about a quarter to halfway at lower speeds, my engine hesitates and starts making a fast chattering/flapping sound from the engine bay, throughout acceleration. It lasts about two seconds or less. Then it stops. The car doesn't seem to lose power. Is this a bad EGR valve? At full throttle or higher speeds, it doesn't seem to do this. It sounds like air escaping a plastic flap valve.

Answer: I’m thinking this is probably a sticking valve or need for adjustment. Also, an exhaust leak can also cause a tapping or flapping sort of noise and a lean condition (engine hesitation) because of the pull of extra air. A vacuum leak may also cause a lean condition under mild acceleration.

Question: The tube/cable connecting the idle air mass valve to the engine compresses when the engine starts in a Toyota Corolla 2009 after I had an engine change. Can someone please help me? Mechanics tell me the valve (cable/tube) is weak but the problem persists upon change.

Answer: You may be referring to the air hose air mass sensor boot to idle control valve. If the hose is collapsing, and it's new, you probably need to buy an OEM part, using also the engine number since you changed engines. Probably you are still using the one for the previous model. Tell the parts person to take a look at the engine and see if he can get the engine number for you.

Question: I have replaced the EGR valve 2 times. Both time the error went straight away. And after 1000 miles, the error came back. May I know what to do now?

Answer: One common issue with EGR valve problems are carbon buildup in the intake and/or exhaust passages. Sometimes, carbon builds up deeper into the intake manifold and cause trouble. Check also the wiring and vacuum hoses (if applicable) that connect to the valve.

Question: I have a ‘05 Dodge Ram 1500. When my truck is cold and I drive it and I reach a stop sign, my truck stalls and looses power. I don’t know if it’s my EGR valve or something else, but doesn’t throw me an EGR code. What could be the problem?

Answer: There could be a problem in the fuel system, bad air/fuel metering when the engine is cold. The common faults are small vacuum leaks, unmetered air to the intake, bad coolant sensor, throttle position sensor faults, sticky (open) EGR valve. This other post may help you with this issue:

https://axleaddict.com/auto-repair/Why-My-Car-Stal...

Question: I replaced the EGR valve on my 1996 Toyota Camry and it still doesn't run strong, why?

Answer: There could be many other reasons for a lack of power. Probably this other post may help:

https://axleaddict.com/auto-repair/What-Causes-Low...

Question: I have a 05' Subaru with 2.5. Whenever pumping gas, the car would stall or wouldn't restart unless I held the gas pedal to the floor. Now, the car will run fine for a minute, and then run real rough before stalling. The throttle is unresponsive. I am not finding vacuum leaks. The car has new wires, plugs, coil and fuel pump. The EGR valve seems to get very hot compared to everything else. Do you have any thoughts?

Answer: Check first for possible pending trouble codes, just in case. It's normal for the EGR valve to get hot, but if it's stuck open, it can cause the engine to stall. Also, check the throttle body for carbon build up around the bore and underneath the plate. Check the throttle position sensor. You may need your repair manual for this, but they're not difficult to inspect.

Question: I have a 2007 Toyota Hilux KUN26R. The EGR valve was replaced, but still throwing P0400 code. Why?

Answer: There could be a problem in the system's circuit. Make sure the valve is opening. If there's no vacuum or the solenoid is faulty, the valve will remain closed. Another common issue is carbon buildup blocking the gas passages. Make sure intake passages are clear.

This other post may help in your diagnostic as well.

https://axleaddict.com/auto-repair/How-to-Test-an-...

Question: Why would cold temperature not allow a starter to work?

Answer: Cold temperature affects battery operation. This is the most common reason, especially if the battery is old or not operating properly. Make sure you have the right battery (CCA - cold cranking amperage) for your model.

Not using the correct oil for the climate in your area can also affect your starter.

Check for clean and tight connections in the starting circuit, including the battery terminals.

Question: I have an old car that I have done a lot of work to, and on my way home after a stop light, I hit a higher rpm to shift up a hill. It hit about 3500 rpm, and it cut out, and had no throttle control. A few seconds later I had throttle control then it cut out again. Then like before it came back but it seemed like it didn't have as much power as it should. Could that be a bad EGR valve?

Answer: If your car has a throttle positon sensor, make sure the signal is increasing smoothly, if it skips it can have sometimes the same symptom. This might help:

https://hubpages.com/auto-repair/How-Do-You-Know-i...

Also, check the fuel system.

Question: Can an EGR valve pressure sensor stop your car from shifting out?

Answer: Performance wise, common bad sensor symptoms show up as engine hesitation, loss of power or even rough idle.

Question: I have a 2016 Nissan Navara NP300. Is it advisable to block the EGR. I have heard that it is advisable to do so to prevent engine damage. What is your opinion?

Answer: The EGR prevents the engine from overheating and forming NOx emissions (very toxic). So it's better not to block it.

Question: I am getting a problem in the transmission in my Ford Ranger XLT, and the company servicing the vehicle says it's the EGR causing that problem. Does the EGR can affect the transmission?

Answer: The EGR valve affects the operation of the engine and the emission system directly. But in modern vehicles, driveability problems can affect transmission operation. The EGR system being an example of this. And many shops are aware of this issue, specially with GM and Ford models. So, it is possible the EGR system is affecting your transmission.

Question:

I hear a sucking noise in my car engine. What does this mean?

Answer: Maybe this post can help:

https://hubpages.com/auto-repair/How-to-Find-and-F...

Question: I have a 2009 Dodge Grand Caravan 4.0 L. It cranks but will not start occasionally. It will smell gas when this happens. I have changed the WIN Module/Cam and Crank Sensors, but there is no code in the computer's memory. Can an EGR valve stop my Dodge Caravan from starting?

Answer: The smell of gas seems suspicious. Too much gasoline is probably flooding the engine. You might want to check the fuel injectors (possibly leaking) and fuel pressure. This post may help you:

https://axleaddict.com/auto-repair/How-to-Test-a-F...

Question: I have a 2009 Ford Focus 2.0. It starts bucking between 2500 and 3000 rpms. It runs fine when the EGR valve is disconnected. I replaced it to no avail. I also cleaned the MAP sensor to no avail. The EGR seems to open and close rapidly when I have light pressure on the accelerator. There is no "check engine" light. Is something upstream causing this?

Answer: There could be a problem with the DPFE sensor; it looks something like this:

https://www.samarins.com/diagnose/sensors/dpfe-sen...

It could be a switching valve problem (vacuum supply problem).

Even if the CEL (engine light) doesn’t come on, check for pending codes.

Question: I have a 1989 Buick LeSabre 3.08, and it will backfire in the intake manifold. It can also be hard to start like it's not getting gas, but once started it runs great. Could this be the EGR valve?

Answer: You might want to check this post:

https://hubpages.com/auto-repair/Engine-Backfires-...

Question: Can a vehicle lose power if the EGR valve is bad?

Answer: Yes, it's possible.

Question: Can a bad EGR valve cause my vehicle to buck on acceleration and then stall out?

Answer: There could be several reasons for this, clogging fuel filter, problems with the ignition system or fuel system.

Question: I have a 2006 Audi A4 TDI. When I'm about 1300m above sea level, the car operates fine, but when I go to the coast, the car loses power as if the turbo stops working. I have taken it for Diagnostics with Audi. They say the EGR valve needs to be replaced. Does this sound like the cause of the problem?

Answer: The EGR system does need to have a specific calibration to respond quickly to changes in demands to the pressure level in the intake system. In this particular case, it's hard to tell if the EGR system is the one affected more by the difference in pressure, but certainly, it is possible.

Question: Can I test an EGR valve by compressing the diaphragm and holding my finger where the vacuum line goes to see if it holds pressure?

Answer: Yes, it is possible. Just make sure not to damage the diaphragm.

Question: I had an EGR valve fail last week with the P0404 code. I replaced the EGR valve, and it was loaded with carbon buildup. I blew the area to try to get rid of the carbon and then sprayed cleaner (carb cleaner) before putting the new part on. It drives WAY better now, but the Check Engine light just came on again a week later and now is throwing the P0420 code, Catalyst system efficiency below threshold. Could it be cat failing because of all that carbon?

Answer: Make sure this is the only code the computer is throwing; otherwise, look first into the other codes. A blocked EGR valve can cause combustion temperatures to rise, creating a lean condition and raising exhaust temperature. This prevents the cat from working properly. If the EGR issue has been fixed (intake and valve passages clear, and the temperature is back to normal), try clearing computer codes as a P0420 can be the result of the previous issue.

If that doesn’t fix the problem, it’s possible the cat or one or more O2 sensors are covered with carbon deposits. Sometimes a cat cleaner will do the job, but you need to check if the sensors are still working correctly. Otherwise, the problem with the cat is more serious.

Maybe this other post can help:

https://hubpages.com/auto-repair/How-to-Check-an-O...

Question: I’ve got the symptoms of a vacuum leak; aka high idle and no power. The car is idling at 1500 to 2000 rpm. Could the EGR cause this problem? I can not find any vacuum leaks, and the EGR is the only component that I haven’t changed yet.

Answer: The EGR gasket may leak. If there are no other symptoms, the source could be somewhere else. Get the codes from the ECM first. The idle air control valve is another possibility. This one is easy to remove and check. Check all vacuum hoses with a piece of hose to listen for noises around the engine.

Question: I have a 1986 Dodge Ram D150 that’s been sitting for years. I got it started today, and there’s smoke coming from underneath the EGR valve. Any idea of why this is happening?

Answer: The EGR valve gasket is probably leaking, allowing exhaust fumes to escape. Remove the valve, clean buildup around the valve and passages, if any, and replace the gasket.

Question: My car lost all power and would not start with the turn of keys. The "EGR" warning light came on the dash--does that mean that my engine needs replacing?

Answer: It could be the valve itself or something in the circuit. Get the trouble code and see if it points to the valve. Even if the valve seems to be at fault, it's a good idea to test the valve. Sometimes another related problem may make the ECU 'think' that the valve is at fault.

Question: I changed the plugs of my 1998 Ford f150 5.4, and then the "check engine" light checked. The shift solenoid B and EGR vacuum regulator is wrong. Could one of these codes make the truck vibrate and run like I have bad plugs?

Answer: Usually, a bad shift solenoid can cause hard shifts, cause the truck jerk when shifting, or shift erratically. Often, a bad EGR vacuum regulator can affect power and increase emissions.

Question: I have a 1996 Acura and the trouble code reading was for the EGR valve. Will a bad EGR valve cause white smoke? The car drives fine and a light smoke comes only when I'm at a red light. And then take off I can see thin white smoke. What does white smoke mean?

Answer: Usually, white smoke is associated with coolant leaking into the exhaust stream, while black smoke is oil getting into the cylinders from a bad piston ring, faulty valve seals or PCV system. This other post may help:

https://axleaddict.com/auto-repair/Exhaust-Color-S...

Question: I have replaced the starter, alternator, fuel pump, spark plugs and wires on my 1998 Jeep Grand Cherokee, but it still won't start or it dies when it does. What else should I do?

Answer: Check the fuel pressure and compare it to specs. You'll need the repair manual for your model.

Question: I have a Passat B6 1.6 FSI. The check engine light is on. I checked it on the reader and it says there is an EGR problem, so I changed it with another one. I drove my car for 100 km, then the light went on again. I changed it again, and the same thing happened. What should I do?

Answer: Check the definitions for the trouble codes; also, a common problem with EGR valves are the passages. Once you remove the valve, you need to check/clean intake passages from carbon deposits that might be obstructing exhaust flow towards the chambers. If there's an obstruction problem, the CEL will keep coming on.

Question: Why is there a recirculation of exhaust gases in a car?

Answer: It reduces the amount of harmful emission -- oxides of nitrogen (NOx). When you mix exhaust gases with the air-fuel mixture, the temperature drops a little bit. This also helps avoid pinging or knocking.

Question: I have a Jaguar XF. The computer states I have a faulty EGR Valve. The only symptom I have is the car won't do more than 50mph (ca. 80 km/h) no matter how much I accelerate. Is it the ERG valve as the engine warning light comes on after about 30 minutes?

Answer: It's better to test the EGR valve and make sure there's where the problem is, even if the computer points to the valve. There could be another problem causing the computer to go into limp or safe mode to prevent more damage. You may need your vehicle repair manual to test the EGR valve.

Question: I have an '87 Nissan Hardbody D21 2WD standard shift. It's got the 2.4L Z24 TBI. My EGR system, I think, has caused head gasket damage. Could the EGR system damage the head gasket? I wanted to make sure it would be OK to delete the system. I'm also going to repair the head gasket now. What's your opinion of the difference between the Blue devil head gasket sealant or thermal gasket? I just bought the truck a few weeks ago.

Answer: A stuck-close or clogged EGR can increase engine temperature. If the problem leads to detonations, it can damage the engine. So it's possible. This problem is more common with EGR cooler failures when it causes loose of coolant. I personally wouldn't recommend deleting the system. It may lead to engine overheating, increase emissions, and driveability issues.

Aftermarket head gasket repair products can do the trick if the damage is not extensive. However, the repair might not be permanent. That said, I've known of people that have some success with Blue Devil and Steel Seal. You may want to do some research and see which will work best for the type of head gasket you are using in your particular application.

Question: I have 99 Chevy 1500. It gave a P0404 code. The guy said EGR valve but the symptoms don't match. It is only hard to start. Turns over but takes 10 tries sometimes. Before only when it sat for more then 10hrs. now will do it even if it was started an hour before. Sometimes it starts after 1 or 2 but sometimes it will kill the battery trying. But once it starts it is perfect quiet as a mouse smooth. Doesn’t cut off. Is that an EGR valve or why would it give p0404?

Answer: This is an electrically controlled valve. The problem could be in the circuit. But the valve can be sticking open, which is reported to the PCM. You may want to try first removing the valve and checking for carbon buildup. The valve can be checked with a scan tool and testing circuit voltages and grounds.

Question: I have a Dodge Caliber 2.0 CRD. It is running at about 150kph, and suddenly lost engine power with no boost. Could it be an EGR fault?

Answer: It seems like pressure built-in the tank (probably a suction control valve problem). Sometimes releasing the fuel cap can help.

Question: I have a 2002 Ford Escape. I changed the EGR valve because it was getting hot and smoking and the rpm would go up but no power. The new one is doing the same thing. What else could it be?

Answer: The EGR could be stuck open. If the engine is fed exhaust fumes continuously, this can overheat the valve, cause poor acceleration. Check the EGR system and see if a bad vacuum solenoid is keeping the valve opened. Check the control circuit as well.

Question: I have a 96 Honda Civic bucks and it slips while trying to take off?

Answer: Check the transmission fluid, level and quality - there could be some transmission problems.

Question: What other symptoms can cause an EGR valve to show that it’s bad or, in other words, causing the engine light to stay on?

Answer: Possibly the EGR valve/intake passages are clogged, or there’s a problem with the EGR system circuit. These other two posts may help:

https://axleaddict.com/auto-repair/How-to-Test-an-...

https://axleaddict.com/auto-repair/EGR-Valve-Clean...

Question: Why is my car making a whining noise after I changed the EGR?

Answer: Check the EGR gasket under the valve. It is probably a leak. Torque the bolts to specs. Make sure the gasket is good though.

Question: Can the EGR valve be closed with a plate on a Duramax Diesel?

Answer: It can be done with a blocker plate, if you find a reliable shop to do it. It's possible that you'll need to clean the valve once in a while if oil from the PCV valve begins to accumulate.

Question: My ‘96 Tahoe develops a front to rear jerking coming from the engine bay at highway speeds and under constant speed, not accelerating or decelerating. When I unplug the EGR wiring dongle the problem disappears. Any thoughts on this?

Answer: The EGR valve may be getting stuck from carbon build up. The jerking you are feeling is probably a vacuum leak. More air entering the engine is upsetting the amount of fuel the computer think it really needs. Check the valve and passages for carbon buildup. Probably other components in the system may be causing this too.

Question: Would a bad EGR valve cause a car to lose power and emit white smoke that smells like fuel?

Answer: Usually, white smoke is associated with coolant leak into the engine. This other post may give more information:

https://axleaddict.com/auto-repair/Exhaust-Color-S...

© 2015 Dan Ferrell

Comments

Dan Ferrell (author) on June 30, 2020:

That'll be a good idea. This is an emissions related code and won't pass.

Richard Belanger on June 30, 2020:

I have a 99 Saturn with a Po40 code, I live in FL with no inspections. I am now in NC and want to sell the car, they have inspections here. should I clean the valve first?

Dan Ferrell (author) on March 14, 2020:

This other post may help you diagnose the problem:

https://axleaddict.com/auto-repair/Why-is-My-Engin...

Hope this helps.

Oves on March 14, 2020:

Hi,

Can EGR cause a car to leak oil? I have changed the turbo recently but oil level is still getting low after 1000miles. I have a BMW 2 series

Dan Ferrell (author) on December 24, 2019:

It seems the valve is not opening. There could be a problem with the solenoid or vacuum. Also, carbon deposits in the intake ports may cause this. The oil may come from a leak in the crankcase ventilation, valve stem seals. Hope this helps.

Paul on December 23, 2019:

Nissan march micra ,i have replaced the egr valve but still after a month check engine light comes on and the code po400 for egr ,there is oil on the valve every time why??

Dan Ferrell (author) on December 12, 2019:

There could be something unusual in the exhaust stream control by the EGR system. The problem could be the control unit for the EGR valve. But originally, the code actually points to the heated oxygen sensor in bank one. This is the exhaust for the side of the engine block where cylinder one is located. There could be a problem with the oxygen sensor, the heating element, or the EGR valve control solenoid. Hope this helps.

Jan on December 12, 2019:

what is Fault code ECM-0038 EGR Control

Dan Ferrell (author) on November 25, 2019:

The code points to a misfire on cylinder number 3. Check the spark plug, wire, coil and fuel injector for that cylinder first. Hope this helps.

Michael on November 23, 2019:

98 Ford Expedition 5.4 L Triton Misfiring at idle and steady driving,only after warm up restart and worse in gear with break applied and ac on.P0303 CEL code??? New Platinum Ford Motorcraft plugs.?

Dan Ferrell (author) on November 23, 2019:

A problem with the fuel injectors (bad, worn) may cause this (too much fuel). But there are a number of issues that can lead to this problem. This other post may help, take a look at section 2:

https://axleaddict.com/auto-repair/Exhaust-Color-S...

Ken on November 23, 2019:

Ford F-250 diesel loss of power started to blow lots of black smoke. This last about two. minutes or so and truck goes back to normal

Dan Ferrell (author) on October 08, 2019:

You might want to double check on the EGR valve, it might not be responding. Test it first before changing any components, if possible. Use the repair manual for your particular model. This other post may help as well:

https://axleaddict.com/auto-repair/How-to-Test-an-...

Donny Doc on October 08, 2019:

Hi folks

I’ve got a bmw 520d lci and I’m having running problems, I plugged it in to the diagnostics and it has came up with dpf and egr, I have removed the dpf and will fit a new one tomorrow, I tried starting the car with no dpf and it’s still running rough, I removed the egr to find it was not jammed, when I take the vacuum pipe off the car seems to run ok, does anyone know if this means the egr is faulty? I haven’t driven the car due to no dpf but it seems to rev freely

Any ideas would be greatly appreciated

Thanks

Donny

Dan Ferrell (author) on September 25, 2019:

Oil, moisture and corrosion can foul a good camshaft sensor and interfere with the ground connection.

Dan Davis on September 24, 2019:

2014 BMW diesel has a egr valve and a egr cooler recall could that cause the engine to break the camshaft because of soot and carbon buildup in the valves?

Dan Ferrell (author) on May 10, 2019:

I'd try first calling a local shop that specializes in your particular model, if necessary. There could be other issues that might come up later on, like power matching between the engine and transmission; other wiring issues as well. You may find wiring harness conversion kits, as necessary. But it's better to talk with a technician that knows more about this before you try any more changes. You may end up investing too much and not getting the results you expect. I hope I could give you a clearer answer.

matthew i angulo on May 10, 2019:

So how do you thing i should go about fixing the issue maybe getting another engine which is a manual matching the transmission would for sure fix it but i wonder if there is another way since the (automatic) engine had no egr i wonder if i swap the housing back to its automatic setting for that but then i would have to worry about the wiring for it there would be a loose plug hmm

Dan Ferrell (author) on May 08, 2019:

The EGR valve for automatic and manual transmissions have different operating configurations because of the way shifting occurs in automatic (regular and consistent) versus manual (according to driver shifting as needed). So your PCM is not getting correct information according to its set parameters. I think this is your main issue here.

matthew i angulo on May 08, 2019:

Hey i have a problem with my 05 Honda civic lx se i did a stock engine swap on it but it was with a automatic engine and the automatic didn't have an egr valve it just had the housing so in order to plug all the wiring in we got the old manual engines housing with that egr valve and put it on the automatic one and it runs fine just the engine light pops up for the egr but i had cleaned it and then replaced it and it needs to pass smog pretty soon any tips?

Dan Ferrell (author) on April 16, 2019:

They should have the proper equipment to diagnose the issue. There could be a problem with the ECU software.

tzzz on April 16, 2019:

Brand new 2017 model toyota prius with 40157 miles shows the same problem EGR valve ,check engine on ,they replaced EGR valve but the problem occurs again .The car is at Toyota dealer six months now and trying to find the root issue as to why the EGR valve keeps failing .Last ubdate that i had from them is that now they are currently waiting further technical advise from the Toyota factory..

Dan Ferrell (author) on March 20, 2019:

Use this as a general guide to test your EGR valve. If necessary, consult the vehicle repair manual for your particular model, specially if you need to test the circuit.

https://axleaddict.com/auto-repair/How-to-Test-an-...

Alex on March 20, 2019:

I'm driving a vw kombi t5 2l model 2010. EGR Valve circuit parmanent and Exhaust gas parmanent

Dan Ferrell (author) on February 21, 2019:

Swap the other ignition coil and see if the misfire follows the coil. This is a simple way to test the coil. But the problem could be in other parts of the ignition system. Also, check the fuel injector on that cylinder if the misfire persists. I don’t think compression is the problem here. Hope this helps.

Gargolanba on February 21, 2019:

Hi,

Im having almost all the problems listed in here. My issue is im getting code P0301. My car when im running in high RPM 3000+ gets the tappin noise but if I accelerate or decelerate it goes off, but if I dont do nothing the check engine turn on and the cars loss like 70% of the power. Next, I have to park the car, turn it off and on again and it is just fine. We have changed one of the coil (2 per cylinder) and the injector but the problem still persist.

Did you think it is the other coil? My car is a Honda Insight 2012.

Andrew Dempster on January 08, 2019:

Over the weekend I cleaned the MAF sensor and the throttle body. Trucks runs great now. I think the opening from the EGR valve to the throttle body was clogged. Thank your for the help. I will look into the other post if the problem occurs again.

Dan Ferrell (author) on January 05, 2019:

A leaking EGR valve is likely to cause a random misfire. Your code seemed to be pointing to cylinder 7. It could still be the one causing problems although adjacent cylinders may have joined. If you’ve verified spark is good now that you replaced ignition components, the problem could be fuel or vacuum (leak) related or even a mechanical problem. I think this other post can help you. But pull down the codes again and see if cylinder 7 still appears or there are other issues. Hope this helps:

https://axleaddict.com/auto-repair/Engine-Misfires...

Andrew Dempster on January 05, 2019:

I recently bought a 2003 F150 V8 4.6L W. It has 289,000 miles on it and it ran perfectly when I bought it. After a few days it had a rough idle, then the check engine light came on. I had it checked at Autozone and it said it was missing on cylinder 7. I drove it a few days later and the check engine light went off (without me doing anything), now it bucks and sputters when idling and accelerating. But stops when I let off the gas. It also seems to run smoother when I take overdrive off. So I went ahead and gave it a tune up, replaced the spark plugs and all of the ignition coils. Didn't work. Still sputters and bucks. It might be getting worse too. Could this be a faulty EGR valve given its miles and age?

Dan Ferrell (author) on January 02, 2019:

Make sure you’ve cleared the codes from the computer memory. Then try this:

* start the engine and let idle until it reaches operating temperature. (about 15-20 minutes)

* increase engine speed to about 2500-300 for three minutes.

Drive for a few days to allow the computer go through the tests/cycles. See if this fix the problem.

Other things to check. Make sure you don’t have other codes besides P0420. Check the other ones first, if there are more. There could be some residual carbon buildup in the intake (ports?). You may try some cleaner like seafoam.

Also, this could mean cat is dirty or there’s a problem with the downstream O2 sensor (clogged with carbon).

You might want to test the sensor first to make sure this is the issue. There are many recipes to clean a sensor, but this is usually not recommended. If the sensor is not performing, just replace it.

If the problem is with the cat, you may want to try a cat cleaner first. Hope this help.

Cody on January 02, 2019:

I replaced the EGR valve and that fixed my problem of the car running poorly as well as got rid of the check engine light (for a little). the Check Engine light is now off and on. Its on for 2 days then off for 2 days and it is teh P0420 code, catalytic converter/O2 Sensor. Could this be a result of the carbon buildup from the EGR valve replacement? I made sure to blow out the area and even sprayed some cleaner there. Or is the O2 sensor or Cat actually bad?

Dan Ferrell (author) on December 21, 2018:

Not necessarily, problems with a borken coil (Ignition coil, fuel pump), dark deposits in the throttle body, a failing or clogged idle air control (IAC) valve, a MAF sensor and other systems (fuel, ignition, air) can cause this problem. Check this other post for more info:

https://axleaddict.com/auto-repair/Why-My-Car-Stal...

But you need to diagnose the problem properly, otherwise you’ll swap parts hoping to solve the problem and spend a lot of money in the process. Sometimes having the car diagnosed, and fixing it yourself (when possible) is a better alternative. Hope this helps.

Colby on December 20, 2018:

My cars is a 2007 ford fusin 3.0.it will start fine when car is on cold start but once the car warms up it will die and will not start.is this a sign of egr falure?

Dan Ferrell (author) on December 18, 2018:

An stuck open EGR valve can make the engine idle rough and stall, but this seems more like a temperature related issue. Have the battery checked if necessary. If it’s cold in the morning, the battery may not be responding properly (slow chemical reaction), especially if it is four to five years old. A cold morning can also make oil thicker and prevent an engine from starting properly.

Raimund on December 18, 2018:

I have a Honda Civic Oriel 2005, It dont start in the morning but it will start when its day light, can EGR valve cause any of this?

Dan Ferrell (author) on December 15, 2018:

This could be a vacuum or gasket leak. You might want to do a compression check. This can make the engine run sluggish. Try having another person fire up the engine while you listen for the sound. Probably you'll be able to tell where the sound is coming from.

Rick on December 15, 2018:

I have a 2012 ram 1500 with the 4.7L with 167,000 miles. Im getting a swooshing compression release sound at start up & seems sluggish. Im not getting any codes or misfires. truck runs smooth but sluggish. I have replaced all plugs & one bad coil but the problem still exist.

Dan Ferrell (author) on November 21, 2018:

This post might help:

https://axleaddict.com/auto-repair/Why-My-Car-Stal...

Alexis on November 21, 2018:

My subran keep stuffing off when I turn and when I stop

Dan Ferrell (author) on October 30, 2018:

Test the EGR valve and see if it's actually stuck open. Probably this post can help you:

https://axleaddict.com/auto-repair/How-to-Test-an-...

Uldis on October 30, 2018:

My Ford Grand C max has not any of symptoms listed but computer shows that EGR is stucked open.

Dan Ferrell (author) on October 22, 2018:

If there's noise while cranking, you might want to check the starter. There could be a problem with the pinion meshing with the flywheel.

Dwane on October 22, 2018:

Hi dan , hsve a 1997 gmc truck 2500 350 5.7L was running some what put new fuel pump in furel filter had it timed up crank and crank no go some times cranking a noise in it ,new plugs i give up

Dan Ferrell (author) on October 09, 2018:

Hi michael,

Start by checking those components indicated in the DTCs -- also, this other post might help as well.

https://axleaddict.com/auto-repair/Why-My-Car-Stal...

michael on October 08, 2018:

hi Dan i have a 96 chrysler sebring with 2.5 v6 it runs fine at times then will just stall out but will usauly start right back and sometimes want stall at all 3 codes came up oxygen sensor heat and oxygen sensor mon. also egr valve but does not idle ruff just stalls out sometimes

Dan Ferrell (author) on September 26, 2018:

This post may help

https://axleaddict.com/auto-repair/Why-My-Car-Stal...

Mutyiri John on September 26, 2018:

Hi Dan

stated

I have a Toyota Vista D4 it idles rough and stalls on red lights,parking lots,or Speed Bumps when engine warms up,I changed the fuel pump and there is little improvement ,this happens when I let go the accelerator and slow down ,the stated RPM on idle as per manufacturer is 650 but it drops down to 550 and 500 then stalls.

could this be an EGR issue.

Dan Ferrell (author) on September 17, 2018:

check the PCV valve and engine oil seals.

Yvonne on September 16, 2018:

Hi I've got blue smoke coming from my exhaust on my vivaro . On excelleration . I've had a new radiator, new cylinder head , new piston rings, cleaned egr valve out and dam is staying on constant. Any advice appreciated

Dan Ferrell (author) on September 11, 2018:

It may cause stalling and rough idling; it is possible in some applications it can prevent you from starting the vehicle. You might want to check it the valve itself or the ports are plugged.

Kurt on September 11, 2018:

Hey mate 08 ranger egr sensor control valve bottom hose has snapped off wpuld this stop car starting at all

Dan Ferrell (author) on August 17, 2018:

The cleaner your mechanic is using is probably decarbonizing the combustion chambers, hence the smoke you see coming out. If there's more carbon inside, you may want to try Seafoam or water - check out this video

https://www.youtube.com/watch?v=KFtp_jmLF3k

EGR valves and passages tend to accumuate carbon and clogg passages, this may be the reason for the APF on the readout. A common practice is to remove the valve and remove carbon manually.

Hope this helps.

Steven CharleHill on August 16, 2018:

I have a 2008 2L Citreon Dispatch

I have had the EGR tested. The computer has said it is the EGR and an Anti Pollution Fault comes across the digital readout on the dash. The van runs out of energy going uphill and seems to flatten out revs wise. Upon resetting the computer, it runs fine for about 10 mins and then it reverts back to the same weakened performance. Mechanic put some cleaning fluid in it and a lot of smoke blew out. I have since put in Diesel Injector Cleaner (mechanic recommended) and see how it goes. Recommended to pursue this form of treatment or not as accessing EGR is a real pain apparently and hence pretty expensive.

Dan Ferrell (author) on August 07, 2018:

Hi Nathan

There'll be performance issues but if the valve sticks open, the engine might overheat.

Good luck

Nathan on August 06, 2018:

Hey,I have had a test done and it shows and all symptoms relate to the egr valve, what could happen if this was left un fixed?

Dan Ferrell (author) on August 02, 2018:

Check the plug wires and the ignition coil. Make sure there's voltage going through.

mbulelo on August 02, 2018:

my toyota corola 1995 model spark plug 1and 2 are not burning ive done the engen and head replace the seals and valves done but it stil doing same thing what might be the problem

Dan Ferrell (author) on June 22, 2018:

Hi JK,

One of the most common faults in an EGR system is carbon buildup. So you can make sure to change the spark plugs, spark plug wires as suggested by the manufacturer schedule. Problems in the ignition and fuel system may also cause problems in the system. So keep an eye on them.

Good luck

James on June 22, 2018:

I have a 03 impala and I’m not sure if it’s the egr or fuel filter or what but I replaced both 02 sensors and it acts like its not getting enough gas and wants to stall but if u give it extra gas the cel will blink and after u let off it will drive fine reminds me of a bad fuel injector and the it backfires when u give it a good amount of gas to get up a hill if not u will slow down really slow

Jukka Kivinen on June 20, 2018:

I got an EGR fault in my Volvo V70 D Automat after 90.000 km:s. It is an expensive job but Volvo factory paid for it as a warranty repair. My question is: can you prevent egr defects in driving style eg. letting Cruise control be on. I used to lower engine rpm:s manually to save fuel

Dan Ferrell (author) on April 30, 2018:

Hi HS,

First get the trouble code, you may need to check the circuit, or a solenoid in the system, before replacing the valve.

Good luck

Hi Sarika on April 30, 2018:

I had my EGR valve cleaned and the check engine light is on again, my fuel consumption has increased. if I continue to drive my vehicle while in ordering the replacement part what are the risks involved?

Thanks

Dan Ferrell (author) on March 27, 2018:

Hi Scott

The check engine light (CEL) might be related to the EGR valve or not. A CEL comes on for different reasons, improperly replacing an air duct after replacing the air filter can be another reason. Get first the trouble codes using a scan tool and see what the computer tells you and go from there. Most auto parts store will now retrieve the codes without charge.

Good luck

Scott on March 27, 2018:

I had my mechanic replace my egr valve and fuel oil and air filter, the car is running like it’s missing and an engine management light comes on as well. It’s a Ford Focus 1.6 tdci (59) . Any thoughts about this thanks

Dan Ferrell (author) on March 08, 2018:

Hi Declan

Usually is better to clear the code, otherwise it'll take longer for the computer to clear and make the necessary adjustments.

Good luck

Declan on March 08, 2018:

Hi i have a 1.9 TID Saab and i need to clean the EGR valve. I was wondering if i have to put it back on the computer to delete the fault after i've done it or will it be ok?

Dan Ferrell (author) on February 22, 2018:

Hi Ran

The EGR valve is normally close at idle.

Good luck

Ran on February 21, 2018:

So how does one go about closing up an egr valve?

Dan Ferrell (author) on February 20, 2018:

Hi LN

That might create a small leak. Have you had a chance to test it? - That might create a problem with the feedback pressure reading for the sensor. If you have the repair manual, you might want to check the position sensor for the valve as well.

Good luck

Larry Neal on February 20, 2018:

hi Dan. 1996 Chevy S10 2.2L. Code P1406. After I cleaned the dog crap out of it i noticed that when i turned the egr valve upside down the pintle fell in a little bit. That should not happen i take it. The pintle should stay out at all times unless i press on it i take it. I am still getting the same code :{

Dan Ferrell (author) on February 06, 2018:

Hi Rgorke,

While it's possible there's a vacuum leak or EGR problems, there are other common faults that can cause a lean mixture:

* MAF sensor

* dirty injectors

* fuel filter clogged

* Worn fuel pump

Check for items affecting bank 2, injectors specially. If you have easy access to the EGR valve, you may want to inspect underneath - carbon deposits and gasket condition.

Good luck

Rgorke on February 04, 2018:

2004 Lincoln LS V8 - Had been getting lean code (P0171/P0174) changed all vacuum lines, Fuel filter, etc. ODB2 reader shows: O-32 EGR Monitor Bank 2: 82 - Manufacturer Specfic, Value 0.126 Min -4.753, Max -4.737

Could this be a clogged or non functioning EGR? Have read the dusty climates (where this LS lived) can clog EGR. Can the EGR be cleaned or in need of a new one?

Also, Short term and long term fuel trims are in right range after car warms up. Maybe a stuck open EGR can mess with fuel trims? Meaning can it mimic a vacuum leak?

Thanks

Dan Ferrell (author) on January 29, 2018:

Hi Travis,

the codes seem to point to specific cylinders (1,6). Have you checked the spark for those cylinders?, there may be a problem in the ignition system or fuel injectors. Usually a faulty EGR valve won't cause misfires to specific cylinders.

Good luck.

Dan Ferrell (author) on January 29, 2018:

Hi Ryan,

There could be many reasons why the engine loses power. But the computer is good at detecting faults at the emissions systems (EGR) - try to get the troube codes with a scanner or take it to an auto parts store for this. Some models are sensitive about non-OEM parts, so it is possible the new valve is the problem.

You can check online for the recommended valve for your model - I recommend going to rock auto.com

Travis on January 29, 2018:

Hi Dan,

I have a 2006 Subaru B9 Tribeca 3.0L H6.

I have been trying to solve a misfire issue for a month now. A P0301, with an occasional P0306 as well. It idles rough, around 1500rpms, normally idles at around 700-800. That idle can fluctuate after being on for while and decrease. The misfires disappear occasionally altogether. I originally thought it to be a intake manifold gasket issue. So I replaced them all. The misfires went away for two days of driving, then came back upon startup on the 3rd day in the same two cylinders. Can an egr valve cause a specific misfire to just 1 or 2 cylinders? Or would it not be all cylinders randomly?

Thanks!

Ryan on January 29, 2018:

Hi Dan,

I have a Ford Focus II 2010 1.6 TDCI. The car loses power at certain points, usually when I get to a high rev. It will then just about maintain the same speed but with little or no acceleration. I brought it back to the seller (under warranty) who changed the EGR valve. It did not fix the issue, but he then told me he just discovered that the EGR valve he used is not fully compatible with Focuses and that I would need a different one. He now refuses to change it or answer calls.

So my questions -

1. Do you think the EGR valve is the issue?

2. If so, which is the correct, compatible EGR valve to purchase so I can take it to another mechanic.

Any help much appreciated.

Thanks

Ryan

Dan Ferrell (author) on January 22, 2018:

Hi JF,

It seems it has a restriction but hard to tell.

Check the vacuum hoses to the PCV valve and to the intake. It's a good idea to check the condition of the EGR valve, but it could also be a sensor giving you trouble. The fact that you have to hold the accelerator may point to a throttle position sensor. Have you checked for DTC (trouble codes) with the scanner?

That could also give you some clues, even if the engine light is not on.

Other possibilities:

bad fuel pressure,

fuel injector dirty,

bad oxygen sensor.

bad IAC (idle air control)

Good luck.

JustFloyd on January 22, 2018:

I have a 1995 GMC C2500 5.7L That has started having a rough idle/stall issue shortly after a cold start. On startup it seems to work fine, but a few miles down the road if I have to stop it will die. The only way to restart is to hold the gas pedal to the floor and crank it. Once it does start it will rough idle and die even if I am reving it to 1500-2000 rpm. Once it thoroughly heats up it seems to run ok. I found the elbow on the nipple at the base of the carb was split. It is the connector from the pcv valve. I replace id and put in a new pcv valve. It ran ok for a couple of days, but has started doing the same thing again. Could it be the egr valve?

Brandon on January 19, 2018:

P.S. I forgot to add that it runs the same if the moter is cold or hot if that makes a difference when it comes to the egr.

Brandon on January 19, 2018:

I have a 95 chevy 1500 with a 5.3 thats throttle body. Ive changed plugs and plug wires, fuel filter, disturber cap, and roter button, the temperature sensor, and i think it was a map sensor i changed also and it still dont want to idle or take gas right at low speeds. If i stop at a stop light it will plum die out if i dont hold the brake and give it a lil gas at the same time. Im going to change the egr valve and egr solenoid tomorrow. Whats the chances of this fixing my truck?? Please help!!

Dan Ferrell (author) on January 13, 2018:

Hi Alicia,

It seems there's something wrong with the electrical system in the EGR system. You want to check that first.

There may be other problems for the low power, perhaps in the ignition system (no spark) or the fuel system. The odor may be fuel.

Good luck

Alicia on January 13, 2018:

Hi Dan , I have a 2000 Chevy Blazer when I drive it doesn't want to pick up speed , didn't even pass 40 miles now not even 25 when I parked Last time it had an odor , my niece put the reader thing it said P0404 do you think is really the egr ???

Farouk on January 11, 2018:

Thank you Dan for your answer, In fact, the fuel filter was so dirty, but I replaced it three weeks ago. Nothing improved though. I scanned the comptuer memory and it indicated a faulty MAP sensor. The Check Engine warning light sometimes on and sometimes off. The engine loses power at around 2000 rpm when I slowly accelerate. But when I accelerate fast it doen't lose power. The engine recovers its power below the 2000 rpm or above it around the 3000 rpm. It doesn't make any abnormal smoke or noise. I cleaned the MAP sensor again but nothing changes. I'll check the catalytic converter and the vacuum line for any leak. Thank you again.

Dan Ferrell (author) on January 09, 2018:

Hi Karol,

The P0405 points to an EGR circuit sensor, did you have it checked yet?

Good luck

Dan Ferrell (author) on January 09, 2018:

Hi Farouk,

I was tempted to say a clogging fuel filter but you said the engine is running good otherwise. Other possibilities are a weak fuel pump, leaking vacuum line, or a clogged catalytic converter, bad ignition timing. Have you scan the computer memory for trouble codes?

Check first for vacuum leaks. Still, when was the last time you replaced the fuel filter?

Good luck.

Farouk on January 09, 2018:

Hi,

Thank you for the article. Astra G 1.7 dti (2004) looses power when it reaches 2000 rpm. I notice this when running on the 1st and the second gear. I cleaned the MAP sensor and the problem seemed to disappear for a few miles but the same symptoms apeared again. I tried another used MAP sensor but the engine shows the same symptoms. As for the idle there is nothing to complain about. There is no smoke. The enginge is in mint conditions.

I still suspect the MAP sensor not being properly cleaned or faulty.

What do you think Den? What could be the real problem?

Thnaks again.

Aamir Wasti on December 31, 2017:

Your page in really helpfull and informative.

Kalei on December 28, 2017:

Hi.. I have a 2001 mitzubishi the last 2 days my car will shut off completely when at a complete stop. I have to hold the break and gas pedal the whole ride so the RPMs won't drop below 1. I've know the egr valuve in the car is bad but could that be the reason for it shutting off my car when at a complete stop? I JUST got it out the shop last week and had a few things done to it already. And it's just draining me and idk what to do. I had the chrank shaft sensor, all spark plugs and wires changed, the water pump and pull system with a brand new timing chain. Also the alternator changed a couple months ago. So everything is basically new besides my EGR valuve

Karol on December 23, 2017:

Hi can anyone help please i have a 2003 Pontiac grand am gt it had the code p0405 I replaced the egr and check engine light came off on its own then i cleared the codes and then i did the drive cycle but it’s still not ready and will fail the smog test what else can it be that its failing? I also scanned it again and no codes are coming up

Dan Ferrell (author) on December 14, 2017:

Hi yasir,

The engine is probably leaking oil into the cylinders, that's why the black smoke. Maybe this explains why the engine lacks power.

Do a compression test to see what is the mechanical condition of the engine. A vacuum test might help too.

Good luck

yasir on December 14, 2017:

I had ford figo 2010 model and car gives back smoke and speed is not increasing above 80 while giving full accerlater and gives a lot of smoke and i also found the air filter getting black help me to solve the problem

Dan Ferrell (author) on December 08, 2017:

Hi Peter

If the emission contains coolant and some oil in the mix, there may be a problem in the cylinder block or head. Possibly a crack, blown head gasket or a mix of problems.

Do a vacuum and compression test to get a more accurate diagnosis before you begin any disassembly. You'll save a lot of time and money.

Good luck

Dan Ferrell (author) on December 04, 2017:

Hi Albert,

If you are testing the valve, for example, and you apply vacuum to it, it should open (rise). Without vacuum, it is normally closed.

Hope it helps.

Good luck

Albert on December 03, 2017:

When compressing the valve on a egr is it supposed to stay in or come back out

Dan Ferrell (author) on November 27, 2017:

Hi Khary

There may be several reasons for this. Check this article for some info:

https://axleaddict.com/auto-repair/Engine-Rough-Id...

Good luck

Khary on November 26, 2017:

I have a 1998 ford expedition with a 5.4 last night as I was driving home it began to have a rough idle can someone please help me out

Dan Ferrell (author) on November 24, 2017:

Hi JM,

Check the EGR system, there may be problems with the sensor, carbon buildup underneath the valve or tubing, or the valve itself may be faulty.

Good luck

James morris on November 24, 2017:

Throttle body is clear put vacume on her valve very little change getting a p0401 code need help what can it be

Dan Ferrell (author) on November 20, 2017:

Hi Sharon

If you haven't seen a puddle of oil on the ground, it's possible you may have a blown head gasket or cracked block or cylinder head.

Is there black smoke coming out of the tail

Have a compression or vacuum test done on the engine.

Good luck

Sharon on November 20, 2017:

What would suck the oil out of the oil pan? Put in a qt of oil. The next day not a drop of oil in the pan.