07-11-2012, 08:24 PM
I have a 2004 Grand Am SE2. Only mod is a CAI. When i start my car after it has been sitting for a while, so cold start, it has a really rough idle and sits at about 1200 rpms. If its thrown into gear the whole car thumps repeatedly and is very uncomfortable. I found that once i start the car and let it sit for 5 minutes or so the RPMs will drop and it will go back to normal with no problem. But this happens every time i start the car after it sits for even an hour. What could be the problem?