My fiance has a 2003 grand am 3.4 liter. It has been idling high and very erratic. It does it sometimes when it's in park, when she is driving, and when she is sitting at a stop light. It's like she has to constantly stand on the brake just to keep the car from taking off on her. Her dad already replaced the idle air control and cleaned the throttle body. I replaced the throttle positioning sensor. These didn't fix the problem. Then a few days ago, I went on this website to try to find an answer. One expert told me it could be the lower intake gasket leaking, creating a vacuum leak, which could cause erratic idling. I knew her lower intake gasket has been bad for a while, so yesterday her dad and I replaced the lower and upper intake gaskets. However, as soon as we turned the car on, it was idling at 2000 rpms, and she had to stand on the brake the whole drive back to our house. I've heard from a couple people that it could be the AC sensor or the computer might need to be reflashed, but I don; t know what to believe anymore. I am at my whits end with this car and my fiance is freaking out, if anyone has any other ideas, PLEASE LET ME KNOW.