I believe that you are stating that the engine revs up and down when in park and stops when placed in gear. This is generally called surging. Look for a vacuum leak. Then check the coolant level to be sure that the coolant is full. Next, warm the engine and purge the cooling system of any air. The air can rest on a sensor and give a false reading to the computer and it is continually trying adjust the mixture to compensate for a bad reading. There are a number of other causes but start there.
Tuesday, November 25th, 2008 AT 9:22 PM
