Most bizarre problem ever...perhaps electrical?

[captainmiller]

Hey everyone, it's been a long time, but I've been caught up in school and stuff. I know this is for a Grand Prix but I can't get decent help anywhere but here...

Symptom: On a cold start, car will be hesitant between 1-2.5k rpms (feels kinda like a misfire), and the 1-2 gear shift seems to come about 1k late, and when it does shift, it IS NOT smooth. If I go WOT I will hit the rev limiter before it has a nasty shift.

Transmission problem? Not at all. If I restart the car, EVERYTHING IS JUST PERFECT - runs flawlessly. To make this more rediculous, this only happens in cold weather. This will never happen during the summer.

- If the car doesn't get cold between restarts it won't happen.
- If it does happen on a cold start, it doesn't matter when the car gets restarted. I can drive it for 2 seconds, notice the problem, throw it in neutral, and restart it. All is fixed.
- Again, never happens in warmer temperatures.
- I had a non-insulated garage space for 4 days, and it got cold out. It never happened for the 4 days. (moisture thing?)

The best part is, I have brought this issue up on several Grand Prix forums, and other people said they had the SAME problem, yet no one had a solution.

One guy said he replaced his PCM and it stopped happening...but thats about it. Help meeeee!

[ChilinMichael]

I was going to just lean towards PCM when I started reading this before hitting the end.....Sounds to me like it could POSSIBLY be related to your cold-loop mode programming. Defaults for the car before it warms up. Why resetting 2 seconds after starting would get it out of that while still cold is beyond me...but it's a possibility. I'm no expert. Disconnect your battery for 10 minutes and let the computer empty. See how your car runs after that from dead cold and after that.

[J Wikoff]

Is your PCM somewhere you can wrap it in a towel and a plastic bag? I'm thinking about keeping out moisture... If they get hot, unwrap it after you start it and see if the behavior changes any.

[captainmiller]

Thanks for the suggestions. The PCM is exposed, it used to be part of the airbox assembly but I have a FWI installed. This problem happened just like it did before I removed from the airbox, so that isn't the problem.

I will try wrapping it something...that is a good idea. Are PCM's typically something that get really hot on thier own? The whole thing is like a giant heatsink, so maybe the heat dissapation is good enough to wrap it in something.

I will try disconnecting the battery, but the car has been disconnected several times in the past when I've been working on it. What does cold-loop mode programming entail?