I have an 02 grand prix gt that i am working on. Its a buddy of mines car and one day we was out riding around and started to have problems. Every time my buddy gets up on it, it miss fires and will buck.. I thought coil pack replaced all 3 still not fixed. Replaced the vacum map sensor and having the same problem. Then his temp light came on one day and fans run all the time. I CE light came on and said the coolant temp sensor was bad. I replaced it and now when you start the car the fans come on run for a min shut off and never kick back on and the car will start to over heat. But if i leave the coolant sensor unpluged the fan run all the time and the car stays kool but the temp gauge doesnt work cuz it is unpluged. I read on here it could be something to do with the PCM thats causing the car to miss fire and buck,and also keep the fans from coming on when they should... I really am lost i dont know what i should do can i reset the PCM or replace it from one in the junkyard. Or is the PCM not my problem at all?? any help would be great cuz this car has me lost ..