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Symptoms of a Bad EGR Valve

Updated on October 27, 2015
Dan Ferrell profile image

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

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EGR valve passages plugged with carbon deposits.
EGR valve passages plugged with carbon deposits. | Source

The same symptoms that indicate a bad EGR valve can also indicate problems in other parts of the system. For instance, you can confuse engine performance problems stemming from a bad EGR valve with problems caused by failures in the spark plugs, the spark plug wires, the fuel filter, the fuel pump regulator, and various engine sensors. So, if you don’t do your troubleshooting, you may end up replacing parts unnecessarily and wasting time and money.

To recognize the potential signs of a failing EGR valve, it helps to know a little about an EGR valve: what it does, what it might look like, and how it works inside the combustion chambers or cylinders.

If you're already familiar with the EGR system, jump to the section below on “Symptoms of a Bad EGR Valve.”

Table of Contents

I. What the EGR Valve Does
II. Types of EGR Valves
III. How the EGR Processes Exhaust Gases
IV. Symptoms of a Bad EGR Valve
V. Troubleshooting

Source

I. 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.

II. Types of EGR Valves

Gasoline and diesel-powered engines have various EGR system designs. Vehicles on the road today may use one of six different valve configurations.

On older vehicle models, you'll recognize the 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.

Different 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)

III. 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 nitrogen gas, creating oxides of nitrogen (NOx) gases, which cause air pollution and human health problems.

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

Source

IV. Symptoms of a Bad EGR Valve

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).
  • Emissions test failure. 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.


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 potentially cause serious 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.

V. Troubleshooting

Are the symptoms above a sign of EGR problems?

Not necessarily.

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.

Because these symptoms vary and be caused by different issues, don’t hesitate to 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.

Also, because cars with electronic EGR valves will have a Check Engine or MIL light on the dashboard, in these cars you can 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.

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    • profile image

      Jeremiah 10 months ago

      Thanks for the article. My only response is to the replacing unnecessary parts wasting time and money. My car has almost 150 thousand miles on it so it would just be replacing the part before it went out.

    • Dan Ferrell profile image
      Author

      Dan Ferrell 10 months ago

      Hi Jeremiah,

      Once miles accumulate, maintenance becomes a priority.

      Thanks for stopping by.

    • profile image

      Peaches 9 months ago

      Thanks for the great info! I have every single one of the symptoms for the open valve, (Okay, well actually our MPG seems like it has INCREASED). As we had our injectors replaced about two years ago, we are really hoping that the new EGR valve will solve our problems! We are also at 150K on a Ford F250 Diesel. Keep your fingers crossed for us please!

    • Dan Ferrell profile image
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      Dan Ferrell 9 months ago

      peaches,

      glad the info helped. Good luck.

    • profile image

      chris 9 months ago

      hi Dan,

      my mk4 golf 1.4 petrol has lost power max speed is 70mph now as the engine light is on been advised my egr is needing to be replaced car is 14 years old and has 128,000 on the clock, will there be damage to any other part of the engine??

    • Dan Ferrell profile image
      Author

      Dan Ferrell 9 months ago

      Hi chris,

      Hopefully not. If it's just recently that the light came on, remove and check the valve. See if there's much carbon build up. You might want to check your repair manual and see the particular check procedure for your model.

      Good luck.

    • profile image

      Louis 8 months ago

      Hi Dan, In last couple of weeks my ford s max 2012 car battery went flat and i had a jump start more than 10times. When engine off, I noticed a 1.5minute beep and click sound from egr valve and it will stop for 30 sec and this will repeat around 30 min from engine stops. Also i can see the above egr valve open symptoms like odor of burned fuel. From saturday i got a malfunction symbol in the dash board and I have given the car to Taylor auto electricians and they said they did not find any drains and they replaced the battery and charged me £209 for diagnostics and battey replacement. I already mentioned egr sound to them, but they said this is quite normal. But still i can see the malfunction symbol in the dash board with computer message for malfunction and now the engine is running in limp mode. Yesterday I have disconnected the electrical connection to the egr valve and drove the car and i can see the engine yellow symbol in the dash board without any computer malfunction message and i got full engine power and limp mode removed, but the computer message comming back when reconnecting egr valve. I assumes that something happened in the electrical side of the egr valve. Could you please advise if i am wrong. Thanks..

    • Dan Ferrell profile image
      Author

      Dan Ferrell 8 months ago

      Hi Louis,

      You didn't mention if the shop checked any TSB (technical service bulletins) on that particular model. It seems to me there is a malfunction in the circuit.

      Since you already spent some money for a diagnostic without any results, why don't you go over to this forum:

      http://www.realworldautomotive.com/forums/

      These guys are pro and it's worthwhile signing up. Give them all the info on your car, the symptoms, tell them what they did in the shop. They'll even check for any TSB for you.

      Good luck.

    • profile image

      cherish 7 months ago

      Will a bad erg valve issue stop your car from starting but start after jumping

    • profile image

      Pumpturbinator 6 months ago

      Just bought My 04 MSM Mazdaspeed MIATA & it will not pass smog. The tester says EGR code reading incomplete. It doesn't give a code or store a code. Now I tried 3 or 4 times to drive the car in high gear then letting it slow down in high gear for over 20 seconds each time. I have driven the car 400 miles. The smog guy took it driving for a hour thinking he could get it to reset. I keep trying to reset the EGR but it doesn't work. Also pulled EGR and cleaned it. Then pulled intake to check it. This is a very clean car almost like new. 65000 miles. Very well taken care of by a old man in Thousand Oaks Ca. Everything is stock. The car runs good but has a rough idle. We have it set about 800-900 rpm. I also checked for a vacuum leek with a propane torch. All checked out good. New plugs, wires, oil change. Do you think Mazda can reprogram the ECU ? What do I try next before I spend big money at the dealer ? Or who do I ask ?

    • Dan Ferrell profile image
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      Dan Ferrell 6 months ago

      Hi Pump

      It seems the ECU should be throwing a code, specially if the EGR has failed. If you're sure there's no problems with the vacuum hoses or EGR sensors' connectors and wires, take the car to a good shop and have diagnose the problem. Hopefully you'll be able to fix it on your own with the diagnostic at hand.

      Good luck.

    • profile image

      Denny 6 months ago

      Dan

      My girlfriend has a 2004 F250 with the 6.0. When she accselerates it makes a loud whining noise. We have replaced the turbo completely. We have replaced some other parts as well trying to trouble shoot it but still nothing. Could it be from the ERG or the AFRG? Wondering if you have any insite on what could be the issue.

    • Dan Ferrell profile image
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      Dan Ferrell 6 months ago

      Hi Danny

      Wonder what made you think it was the turbo. It's hard to tell without other potential clues. Have you thought of the drive belt? If you rev it up at idle, does it make the same noise? If so, you can use a piece of hose to listen to the pulleys, and idle pulley. A slipping belt whines when worn out or a pulley is out of alignment. If that check fails, stop by this forum:

      http://www.realworldautomotive.com/

      they get access to TBS just in case.

      Don't change components until you get a more accurate diagnostic.

      Good luck.

    • profile image

      Terry 5 months ago

      Hi there,I have a Toyota avensis 2.2 d4d car,my car will not start ,I had a crecorder in the car from the previous owner and I took it out ,it will not start now,I plugged the crecorder back into the car and still no luck,I have had a computer on it and it said egrvalve on computer,I have taken out the egr valve and cleaned it ,still nothing ,could it be ecu error and what do I do

    • Dan Ferrell profile image
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      Dan Ferrell 5 months ago

      Hi Terry,

      Make sure to check any EGR sensors, electrical connectors and wires. The computer is pointing you in the direction of the circuit not necessarily to the valve, although this could be your problem. Use the repair manual for your particular model to test the EGR valve and solenoid to pinpoint the problem.

      Good luck

    • profile image

      Jim 5 months ago

      Dan, I have a 93 F150 5.0 and so far have replaced throttle position sensor, EGR speed sensors and exhaust manifolds. Check engine light still comes on and after it comes on, I notice a decrease in power, especially on hills. Any suggestions?

    • Dan Ferrell profile image
      Author

      Dan Ferrell 5 months ago

      Hi Jim,

      First check what diagnostic trouble codes (DTCs) are stored in the computer. If you don't have a scanner go to an auto parts store, usually they'll retrieve the codes for your. When reading the codes, remember that the computer can only point you to the circuit it detected the "error" coming from; it won't tell you if an specific component went bad. You need to test the sensors, actuators, connectors, grounds, incoming power, etc on that particular circuit to find the fault.

      If a code points to the EGR, test the egr, the egr-sensor, any vacuum connected to it, electrical connectors, wires, etc.

      Good luck.

    • profile image

      Dilly 5 months ago

      I have a Mini Cooper s & when I'm in a traffic jam, stop start for about 20 mins the engine fan comes on, followed by the turbo light coming on then the engine coughing & spluttering & dying! Could this be the egr valve? It only happens when it gets hot & in this sort of traffic.

    • Dan Ferrell profile image
      Author

      Dan Ferrell 5 months ago

      Hi Dilly,

      Check for any DTCs from the computer first, you can go to autozone or your local auto parts store. Have them pulled any codes from the computer and start from there.

      Good luck.

    • profile image

      Berttrim 4 months ago

      Hi,

      I wonder if someone could give me some information about a problem with my 1999 Nissan quest. This is virgin territory for me. A rhythmic bucking while standing at lights or in drive. Regular driving is better, but with the occasional bucking. When starting from cold it seems quite normal until warm 5 to 8 min. New alternator, not an ignition problem. Tested throttle body housing. I'm guessing EGR plugged, or Cat. No codes on dash. Before I dive headlong into this, does anyone have any other ideas. Thanks

    • profile image

      eldrun 4 months ago

      hi

      I have got a jeep cherokee 2004 2.8 diesel. I am blowing white smoke through the exhaust.performance is affected and also fuel consumption is very high. please advise on my option on fixing the problem.

      it was initially thought that the turbo was was bad and burning out oil so had that replaced and was told after a few 100 mile it should stop but still have not. so question is is it my injectors or EGR valve or something else

      thanks

    • Dan Ferrell profile image
      Author

      Dan Ferrell 4 months ago

      Hi Berttrim,

      It wouldn't hurt to take a look at the EGR passages. If you haven't done in the last couple of years, there might be some gunk stuck in there. The valve may open but buildup may prevent gases from flowing back in. Take a look and clean up as much as you can.

      Good luck.

    • Dan Ferrell profile image
      Author

      Dan Ferrell 4 months ago

      Hi eldrun,

      have you done a compression check yet? If the white smoke is continuous you might have a blown gasket. You can do the compression check yourself with a special gauge, go to this link for the steps:

      https://axleaddict.com/redir/?redirectUrl=https%3A...

      Good luck

    • profile image

      slkdnichols 4 months ago

      I have a 2008 Dodge Charger with the 3.5L. I just had the timing belt replaced (I know I am late) and had recalls done on the same day. The recalls included the driver side airbag, FOBIK and ignition. Since that day, I have been having issues with the car. It is idling a little rough, I have lost hp and it doesn't shift down properly. In addition to that, I have had issues starting the car. I will turn the key all the way, let go of the key and the car starts after a second or two. Yesterday, I turned the key, I waited for the delay, the car started and then died... and then started again by itself without me touching anything!!! The dealership says that it isn't an ignition issue and the mechanic says that they didn't do anything when changing the timing belt! oh, one last thing, I was on my way home last week; the traction control and ESP/BAS lights both came on. They went back off after I let the car sit for a while at the house (turned off). HELP

    • profile image

      slkdnichols 4 months ago

      In addition to the comment above... I thought it might be the EGR valve that is having the issues... and it is just a coincidence that it happened at the same time as the ignition and timing belt were replaced. :)

    • Dan Ferrell profile image
      Author

      Dan Ferrell 4 months ago

      Hi slkdnichols,

      it does sounds like an ignition issue. If they didn't replace anything from the ignition system maybe they left something unplug or not well connected (?). Did they tell you what the ignnition recall about? Did they replace something? Also, if they moved-replace something and system service is overdue, worn out ignition components will not handle power properly as per the new components.

      I'll start with this recommendations.

      Good luck

    • profile image

      Annie 3 months ago

      Hi Dan,

      I hope you can help. I have an Audi A4 tdi 2008 Cabriolet.

      Three weeks ago I stared getting some white smoke from my exhaust and an almost sweet smell with it. I took it to a garage where they had a good look. After a couple of weeks they have changed the EGR Cooler, rocker cover unit ( due to heavy sludge build up) 3 engine flushes, new engine oil filter, new air filter and replaced the engine oil.

      I have driven it home from work for the first time since having it back (30 miles) and noticed smoke from under the bonnet. I opened the bonnet and there was smoke coming out from around the oil cap....

      Is this normal after all of the work I have had done? I have just spent the best part of £900 on the repairs and I am now really worried about this new problem.

      Thank you in advance.

      Annie

    • Dan Ferrell profile image
      Author

      Dan Ferrell 3 months ago

      Hi Annie,

      sorry for the late response. You definitley need to have it check. That's not normal. Did they put too much oil in it? Did they put everything back the way they were supposed to? I hope that by now you've taken the car back and have it checked.

      Good luck.

    • profile image

      Mark Williams 3 months ago

      It seems Dan that I have high detonations when I go up hills on roads when I'm pressing on the gas pedal. My vehicle is a 1999 Chevy S10 truck, LS extend cab 4 cylinder 2 door and I have no EGR sensors that will trigger the EGR valve for my light to come. I did change the Fuel Filter, the tensioner and pulley, 3 TCC solenoids in the transmission since 1 did come up for the service engine light, and cleaned off the Idle Air Control Valve and passage. With high detonation while driving up hills , do you think my EGR valve is bad now or I should check my EGR valve out too? Also, new Air Filter, Oil Filter has been replaced but same sound still, plus sometimes the truck jerks after 1st gear, it can't be any solenoids in my Automatic transmission because they're new.

    • Dan Ferrell profile image
      Author

      Dan Ferrell 3 months ago

      Hi Mark,

      It'll be a good idea to check the EGR valve as well and have you tried to scan the computer? Any codes? Check for possible misfires. It seems more than one symptom due to maintenance.

      Good luck.

    • profile image

      Arthur Leite 3 months ago

      Hi Dan, I have an Mitsubishi Pajero/Montero Full Diesel V98W motor and almost thee weeks ago motor light turned on, I passed scan show us EGR fail, I oppened it an complete carbonized so I cleanned careffuly with Wd40 reset but motor light return and still ON, so my doubts are: 1- Is possible to drive car with this EGR Valve? Is it cause any damage? 2- Mitsubishi EGR is eletronic so how can I test it? 3- There are some sites that reccommend close/cover EGR open for definitely, is it possible and make sense?

      One sympton I identified is, when turno of the car by key there is a delay for motor shut of about 1 or 2 seconds, only turn of, no more issues...

      Thank you in advance.

    • Dan Ferrell profile image
      Author

      Dan Ferrell 2 months ago

      Hi Arthur,

      Sorry for the late answer. I was having issues with my browser and didn't see some of the posted comments. The short answer to the issu is: it depends on the particular failure of the EGR. Did you try to erase the code after decarbonizing the valve passages? Did it come back on? If so it is a good idea to test the EGR. You have an electronic device. The vehicle repair manual for your particular car may show you the way to troubleshoot the valve and related componets. You can buy an aftermarket copy online, try Amazon or your local auto parts store. You say there doesn't seem to be any issues except the small delay when you turn off the motor. That seems to be a little bit of diesling. Probably you already fix the vavle, but you need to double check. Try erasing the code, if you haven't done so yet. If the light goes away thats a good sign otherwise do more testing and a re-scan.

      good luck.

    • profile image

      Tazz William's 7 weeks ago

      I have a 99Sebring the car runs great,but Theres one problem thats driving me crazy. The car starts and drives but after a short time it will stall out. Put it in netrual or park and it starts right back up and down the road you go. Sometimes a few blocks sometimes few miles. Them it does it again throw it in neutral and it starts right back up and away you go. Mostly at stop signs or into slow curves. I've checked everything I can think of. Please help Whats wrong with this thing??

    • Dan Ferrell profile image
      Author

      Dan Ferrell 6 weeks ago

      Hi Tazz

      Usually when a gas pump or ignnition modules is going it'll show those same symptoms. After the car stalls, you need to let the pump or ignition module to cool and then it'll start. But seems like you can start the engine right away. Have you checked the neutral safety switch for adjustment or wear, the connection at the ignition, even something as simple as a clogging fuel filter can be causing this. Also, check the battery cables at the terminals. If some threads are broken, vibration eventually may put a lot of current resistance.

      Good luck.

    • profile image

      Dominique jones 5 weeks ago

      Hi! I have an 2005 chevy cobalt .

      My car is doing the same thing! Every time I stop or slow down it just dies out and tries to start itself up again! The car has been in the shop 3 times and everyone keeps guessing , I've had the spark plugs replaced , the fuel filter , and the battery recharged cause sometimes it just dies and it won't take a jump . I've spent so much unnecessary money it's ridiculous. I don't know what to do . Do you think it's the EGR Valve ? Any advice will help please and thank you !

    • Dan Ferrell profile image
      Author

      Dan Ferrell 5 weeks ago

      Hi DJ,

      If you've noticed this problem at idle most of the time, yes it could be a problem with the EGR valve (or carbon build up at the ports, for example). But you can also have other issues:

      * Idle speed valve , carbon buildup at passages (remove and check) or a device malfunction.

      * MAF (have you check for a dirty valve?, possibley you'll need a scan tool to check operation but consult the repair manual for troubleshooting checks for your MAF.

      * It could be something as simple as a clogging air filter - when was the last time you replace it (evey one or two years is the recommended)

      * check for possible vacuum leaks - at high speeds a small leak won't give you trouble but you'll notice at slow speeds.

      * Also, check the throttle position sensor (TPS)

      https://axleaddict.com/redir/?redirectUrl=https%3A...

      I would start with the most simple items and don't forget to scan your computer for possicle trouble codes. If you don't have a scan tool, your local auto parts store can get the codes for you for free.

      Good luck.

    • profile image

      Cameron 4 weeks ago

      I have a 2006 civic EX 270,000 on the stock cat it seems. The motor was swapped and has around 150,xxx. On random mornings I start the car with a rough idle and when given gas disappears immediately. While cruising in gear until it's warmed up sufficiently if I back off the gas all the way I get almost a studder sound coming from the motor, when the motor has been driven for x amount of Miles it goes away. Normally if the car is started within a few hours of its last shut down it will start with no vibration. Some days it starts completely normal with no vibration. I have a test pipe (in a state with no emissions) and while I take the stock cat off I believe this will be the first place I look further. If it is dirty as can be then I will clean it and replace the plugs. If the random rough idle continues where do I go from here?

    • profile image

      Anthony Maragni 4 weeks ago

      Your information is very helpful my problem is 02 Chevrolet Silverado 4.8 when wet or damp misfire occurs clears up after 10 to 20 minutes new wires and plugs and coil packs HELP I am lost

    • Dan Ferrell profile image
      Author

      Dan Ferrell 4 weeks ago

      Hi Cameron,

      From what you describe, it seems you got a cold start problem. Have you checked for any DTC (computer trouble codes)? Go to an auto parts store and have them get the DTCs for you.

      I don't think the cat will give you this cold-start problem. You'd loose power if it was clogged.

      Good luck.

      ------

      Hi AM

      Have you checked the MAF sensor - although it shouldn't fail only on humid days, give it a try. Make sure it's clean and the harness and wires are in good condition.

      Good luck

    • profile image

      Susan 3 weeks ago

      I have 1997 Civic. Alternator went bad and was replaced, along with the battery. A week later, threw a code of P1509 (air idle control sensor), and a few days later started bucking while driving. Had distributor cap, plugs, wires replaced and ran okay for a few days, then started bucking again. Next fuel filter replaced, and it was good for the repair shop, but started back up again later that day. Was hoping it was bad gas, but not so sure now. Started to buck after about 10 minutes of driving, hesitates/bucks when accelerating from a stop, bucks if I let off the gas, and sometimes just shakes when driving. The idle didn't start acting up (racing) until a couple weeks into this problem. My tach stopped working, maybe when it threw the code originally, but not sure. I've put fuel injector cleaner and dry gas in the last two tanks of gas (am still on first tank of gas after fuel filter replaced). Could it be the air idle sensor causing this, even though the symptoms happen mostly while I'm driving, or could it be ERG, or something else? Thanks!!!

    • Dan Ferrell profile image
      Author

      Dan Ferrell 3 weeks ago

      Hi Susan,

      Buildup can block proper operation for the IAC (idle air control) solenoid, and mislead the car computer about the angle of the throttle valve (plate) position. Have your mechanic remove the IAC and check for buildup and torubleshoot the IAC to make sure it is working as it should. Problems with the EGR valve itself may show up at idle or at higher speeds. If necessary, have it checked too.

      Good luck.

    • profile image

      asrar 2 weeks ago

      Hi dan

      I have vw passat diesel when i am traveling at 70 mph and going up hill when i press gas paddle the engine goes in to limp mode.

      I have cleaned the egr valve but no change can you help.

    • profile image

      Jesse 2 weeks ago

      Hello, I'm having issues diagnosing a stalling issue with my 91 full size blazer with the 350tbi.

      Everything ignition wise have been inspected or replaced, fuel pressure is good and injectors are good. When at idle it will slowly lose rmp and die, when placed in gear or stopping at a red light it will stall also. Could it be an EGR issue? Thanks!

    • Dan Ferrell profile image
      Author

      Dan Ferrell 2 weeks ago

      Hi J,

      Yes, it could be. If the EGR sticks open, it could stall the engine at idle.

      But there are a number of sensors and issues that may cause this symptom as well. Have you try scannin for trouble codes?

      Even if you don't see the check engine light come on, you could

      have some pending codes that might help you.

      Good luck.

    • Dan Ferrell profile image
      Author

      Dan Ferrell 2 weeks ago

      Hi asrar

      It seems your computer when into "survival mode". it probably detected one or more sensor going out of range. Then it put the transmission in single gear for safety. You should take your car to the shop to have them scan for trouble codes and diagnostic. And it should be a priority.

      Good luck.

    • profile image

      Andre 2 weeks ago

      Hi Dan,

      I have 2010 VW Routan, 6 cylinders, 4L with about 195000km.

      Last two months I have a problem with car shutting off without any warning or lights on dashboard. My car mechanic friend plugged his computer and there was no error code on it. He decided to change crankshaft sensor. After that, no change. We plugged computer in again and took it for a ride. We got ECT error. We replaced this sensor, and , no change. It seems that when I start the car ECT info is in black, it changes to red about 130 degrees Fahrenheit. After talking to my friend we decided to take it to the dealer. Car shut off just 5 km before I reached dealer. I explained everything to them and ... they couldn't find any error codes neither. However they told me that they had similar issue with different car and they replaced EGR valve.

      Would faulty EGR valve cause car to shut off on the road? As I mention that happen without any warning, sometimes when I just start to drive (cold engine) sometimes when I am doing 100km/hr on highway (hot engine). No warning light on dashboard, nothing, just shuts off. Any idea?

      Thank you

      Regards

      Andrzej

    • Dan Ferrell profile image
      Author

      Dan Ferrell 2 weeks ago

      Hi Andre,

      If the EGR sticks closed, it'll cause the engine to run hot. So it is possible the ECU is shutting off the engine. However, the ECT should signal a higher than 200F for the ECU to consider the situation critical. Otherwise the engine should be within temperature range.

      You should check the ECT circuit voltage using a voltmmeter. Also check the connectors for loose wires and wires condition.

      Also, it's possible for you to check the EGR valve.

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

      Did you ask the dealer about possible TSB (technical service bulletins) on your model?

      Good luck

    • profile image

      Larry 2 weeks ago

      Would faulty EGR valve cause van not to start? 2007 Chrysler Town & County. We had the van hooked up to a computer a couple of weeks ago and the code returned an EGR Valve problem. We did not have it fixed at that time.

    • Dan Ferrell profile image
      Author

      Dan Ferrell 2 weeks ago

      Hi Larry,

      If the EGR valve sticks open, it'll cause a rough idle and likely to stall. If you already got a EGR trouble code, you should check it, it might be causing your no start unless you also got some starting relating issues.

      You can test the valve at home:

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

      Good luck.

    • profile image

      Cass 7 days ago

      I have a 99 Buick lesabre that's check engine light is on. The fiance took the car to guy with a reader and he told her it was an egr valve code. After its warmed up and been running a while it dies when you slow down but it stays right up afterwards, but the only way to keep it running is to keep foot on the gas even when coming to a stop, any ideas would be appreciated before I buy a valve and replace it. Thank you.

    • Dan Ferrell profile image
      Author

      Dan Ferrell 7 days ago

      Hi Cass,

      You need to have the EGR tested first. The valve could be sticking. Also, a sensor can be sending the wrong signal and causing the computer to wrongly lean the mixture when it should not.

      Good luck.

    • Don Dragodon profile image

      Don Dragodon 2 days ago

      I have a 2001 Ford Focus ZX3. It has bee sounding rough since I got it. It sounds like I'm driving a muscle car with a head cold. It shakes and vibrates while I'm driving and even more when I'm stopped. On some rare occasions it has stalled out on idle. I lose horsepower at times, especially going up slight inclines and has terrible gas mileage. I tried fixing several things including a new timing belt, flex pipe, and a new coil pack, but nothing has changed. A friend of mine just recently mentioned the EGR valve. Could these symptoms point to that and how much does a mechanic usually charge to check the valve? The car starts up fine, but loud, and the check engine light has not come on (yet).

    • Dan Ferrell profile image
      Author

      Dan Ferrell 41 hours ago

      Hi DD,

      From what you describe it seems there's an exhaust or vacuum leak. Hard to tell, but if the engine doesn't improve at any speed range, I don't think it is the EGR valve. Check for leaks and check the exhaust manifold and gasket. It wouldn't hurt to scan the computer as well. You may have a pending code that hasn't "surfaced" yet.

      Good luck.

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