Troubleshooting rough idle 95 PAU

[Schlotzky]

Any tips on how to test the ICM? And where exactly it is/what it looks like? Maybe be worth it to just replace it with a unit from a wrecker? Possibly with the PCM as well.. the place I go to seems to be dirt cheap when it comes to non-essential parts.

[Jrs3800]

Advance Auto Parts or Autozone should be able to test it... Most of the time it will take a series of repeat tests to heat the module up to see if it hit a failure.... The test will sometimes say its good when its not always the case..

The ICM lives under the coils, remove the 3 coils and you'll see the ICM... You will have to remove the wire harness from it..

The PCM is a good failure point on these cars... If you can get an ICM and PCM cheap enough I would pick up both... Its good to have a spare of these 2 items especially when you get up in age and miles with these 3800's..

My money is still on the PCM tho.. Just remember I can't promise this, so I could be wrong........ But thats where my money is...

[Schlotzky]

Ah, THAT ICM. lol. Yeah, all the cars at the yards I go to don't have engines. PCM should be easy enough to get a hold of, but I will see if I can get the icm tested.

[Schlotzky]

I've got a 96 Camaro with the 3800 Series II. Do these cars use the same ICM? That'd be an easy free swap to check if so.

[Schlotzky]

According to Rock Auto parts catalog, they two cars use the same ICM. I'll see if I can swap them out and report back.

[Schlotzky]

The car is running similarly with the icm from my other car, but I'm going to keep it in for a while and see if the SES light comes on again. The PCM is the best place to jump next?

[Jrs3800]

Originally Posted by Schlotzky

The car is running similarly with the icm from my other car, but I'm going to keep it in for a while and see if the SES light comes on again. The PCM is the best place to jump next?

Thats where I would be looking next..

[Schlotzky]

Thanks for all the help. I'll follow up when I have some new info.

[Schlotzky]

Changed out the pcm with one from a bonneville. When I took mine out, I was surprised to see that the car already had a GM Re-manufactured PCM. It hasn't thrown a code since the ICM swap, nor has it run super rough as it did when it threw codes, but it's still not idling smooth and while I haven't measured the gas mileage since the swaps, it seems to be similar based on mileage vs gas needle. (15-16 mixed)

The only thing I can think of for gas mileage that I haven't done is the o2 sensors, but I can't imagine that would cause the rough idle.