I recently purchased a 2004 coupe. When I stop at stoplights or intersections the idle drops to 500rpm and the car is slightly rough at idle. As soon as it turns green and I accelerate there are no issues. I actually called the dealer who services the car before I bought it and he said that it is normal for the crossfire. It lowers the idle at stop and then resets after you accelerate. Anyone else have this with their car?