I've had this problem since I first got the car. When I first start the car up in the morning the idle shoots up to around 2000 and then bounces between 2000 and 1500. If you let the car sit long enough it will go down to about 1200 or 1300 but still doesn't go to normal idle and when you shift into reverse the whole car jolts very badly. Most of the time it only does this in the mornings but on occasion it will do it if the car has been sitting for several hours. Any suggestions?