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.
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Wednesday, November 28th, 2012 AT 4:55 PM