I had my head gasket cracked in my cavalier as well. Basically when this happened I had to have the entire engine replaced because the car was over 100,000 miles. You could do a sealant, but that wont be good forever. Anyways, once they repaired my issue with a new engine, still I started the car and the idle was high ever since. I have been to so many mechanics and they are all stating it is normal. Ive been driving it like that for months now and no issues. It's a very wierd car. Be prepared for the following to happen in the future: Fuel pump blows for no reason, electronic issue where all the lights on your dash light up randomly such as anywhere from the seatbelt light, to the oil, highbeams, and check engine light, all at once. The window motor blowing, front suspension noise heard on turns. Sell the car if you can. I have nightmares everynight about mine.