Why does my engine rev up and down on a manual transmission on a 87 Acura legend
Oct 25, 2012 at 3:32 PM
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KHLOW2008
CERTIFIED EXPERT
41,814 POSTS
If the idling speed is too high, idle would surge. Lack of coolant or clogged coolant hoses to the cold start and IAC can cause this too. Vacuum leaks, bad cold start valve are other possibilities.