Random Misfire

[sliles17]

2000 Grand Am - Took it to Autozone pulled 0300 random misfire code. Did some research on here and replaced the coils, didn't help. Ran plug wires from the module to the plugs and pulled them off and all are getting spark. New spark plugs as well. Also pulled injector clips off and all are firing fuel (car dropped RPM when pulled). Pulled fuel rail and injectors and cleaned em all up to be safe. Cleaned out the throttle body and idle air control as well.

So....car is getting spark and fuel but runs like a dog, sputters. Traction Control light is on also. Read somewhere that it's strictly an electrical problem with the Body Control Module or something? Anyone have any insight?

Hate to say it here but I will never buy a Ponti again...cars been nothing but headache since it hit 85K.

[450HP]

What brand of plugs are you running?

Scott

[sliles17]

AC Delco's

[Big-Z]

my car runns smooth, but can randomly mis fire with no codes. a guy said it could just be the computer doing that to heat the cat. converter

[xeroinfinity]

Random misfires are typical with these models.

If you have replaced everything but the ignition control module(under the coils) that could be bad.
Could also have a wire damaged on the ICM or in the injectors harness. A bad injector harness ground will also cause misfires and is a common problem.

You will need to clear the code if thier was a SES light on with the engine running poorly.
And autozones free scan doesnt always read all trouble codes, especialy ABS and Tracion control DTC's.

Good luck

[sliles17]

Well we got it fixed, turned out to be a bad fuel pressure regulator.....

When you'd pop the vacuum line off gas would come out the top, Pontiac service wanted to charge 450 bucks. Picked the car up and changed it out myself in 15 minutes in the parking lot for 80 bucks...unreal. Unfortunately w/ the car misfiring it developed a rod knock so we had to get rid of it.

Hopefully this helps someone else stuck like I was.