Yes, surging is the term we normally use for such conditions.
Problem is due to erratic idling speed. When this occurs, the PCM would try to compensate and the idle would surge.
Possible causes are
1. Low idling speed. Air passage restriction would reduce the idling speed. Cleaning the throttle body and idle valve should help if there are no other faults.
2. Misfiring. If the engine is not running correctly due to bad spark plugs or related parts, the the idling speed would drop.
3. Vacumn leakages. If any vacumn leakage occurs between the MAF and throttle body, idle would be erratic.
Is the Check Engine Lamp indicating?
Sunday, September 19th, 2010 AT 9:30 AM