Hello,
I have a 2005 Grand Prix GTP CompG that has been doing something really weird since I have owned it over the last 2 years. It's really starting to piss me off.
Every so often, when I cold start the car and start driving, it bogs down during acceleration in the first gear. It seems to miss the 1 - 2 shift and it eventually shifts late as the RPM's climb and sorta thuds into second gear. If I restart the car, it runs like a champ. No missed shifts, perfect acceleration.
It is also temperature related. This will almost never happen during the summer, and will happen almost every cold start in the winter. As the temps start to dip this fall, it is starting to become frequent again. And all it takes is a restart, immediately after the first one, to fix everything.
All I can think of is a bad PCM that is somehow weather affected, or maybe some sort of solenoid in the transmission. I have posted this before on a few GP sites and a few other guys will chime in and say they have this issue too, but no one offers a solution. I will be forever in debt to any person who has an idea as to why this is happening.
Thanks for your time!!!
