Sypmtom is known as surging and this is due to excessive high idle.
Possible causes are:
Lack of coolant.
Idling speed adjusted to high.
Faulty Idle Air Control (IAC) valve.
Cold start valve(fast idle thermo valve(FITV)).
Clogged coolant hoses to FITV and IAC.
Wednesday, November 28th, 2012 AT 4:55 PM