I have the same car. My car idles at the same rpm's you described. I also notice that there is some undesireable motion. I'm sure this is normal. It's related to the high performance charecteristics of the engine. My engine is brand new. The previous owner had it replaced IW a year ago. OK, so I guess its a year old, not brand new...but anyway, I doubt there is anything wrong with it. You do know about the "recall" on the engines from that year? If not search the board for prevoius info.