Hi,

I'm at my wits end trying to figure out this problem. My car'* got almost 200,000 miles and was running good with no major problems. Then the car starting stuttering at random and is getting worse. Sometimes it runs just fine for awhile and then starts up again, the check engine light might come on for a few minutes and then go out. So far I've replaced the fuel filter, fuel pump, and fuel relay. Also replace the Mass Airflow Sensor, new plugs, wires and checked the coils. Any ideas would be greatly appreciated.

thanks,

Keith D.

How about your O2 sensor? How did the plugs look when you pulled them?

Check to make sure your spark plug wires are not touching the o2 sensor wires. If they touch it might make your car act like your describing.

did you check the cat? I seafoamed mine and it bucked a lot and then took it on a long ride and heated it up.It went ok after that.

i would check the coils again

AND check for the dreaded vacuum leak................I had one at the tranny vacuum modulator that kinda had those symptoms..........

Also check the PCV valve.

Does it do this going up or down a hill, when engine is warmed up or while it is still cold, right after you let off the gas?

I'm having a very similar problem with my 95 SE with 175k. It stutters and bucks at light acceleration (when traveling on highway). No engine light though. I replaced plugs and checked all fluids. Old plugs looked great. Is there a way to test the PCV? Also, can I put a vacuum pump on the modulator to test that? Thanks, Tom

Here'* how to change and check the PCV valve. It'* on a supercharged engine but checking yours is the same.

https://www.gmforum.com/t279060/

You will also want to test your coils and plug wires if your engine is stuttering. There'* a procedure for that in the tech info area as well.