Idle speed at cold start is about 1100 then falls to 800 or so. Then it runs back up to 1100 and will fluctuate from 900 to 1100 until it is put in gear, which sends it back to about 750. After the car is run for a while, it idles at 1100...Does anybody know what's going on. The dealer had the car for two days and replaced the coolant temp sensor...no help.