i think when idling, the idle speed sensor will determine our idling speed base on the engine temperature. when the engine is cold, the rpm will high a bit. and will the rpm will drop down when the engine is already warm. maybe that sensor need to be cleaned to make it work properly. cleaning your throttle body also might help as the sensor hole is located at the throttle body.

This post has been edited by ledtechn: Nov 1 2012, 04:14 PM