Most likely, the spark plugs need to be changed. The interval for changing spark plugs varies from every 30k miles to every 100k miles depending on many factors such as driving conditions, gasoline quality, and especially the type/quality of spark plugs that are in the vehicle. A valve adjustment is also likely needed as well if it has not been done previously. Drive belts may or may not need to be replaced depending on their condition. When my Honda Civic hit 100k miles, I changed the timing belt, water pump, serpentine belts, spark plugs, and adjusted the valves. This was 80,000 miles ago and I haven’t had any problems with the car since.