Car is 1993 Ford Escort Wagon on start up idle goes up and down pulses. After warms up say 30 minutes seems to go away most of the time…At times it will die if in drive and cold. Any ideas Many Thanks Chris
Disconnect the electrical connector from the iac (idle air control) valve, and see what happens. Here are pictures and words to show you what the iac is. Click on this link: http://www.autozone.com/servlet/UiBroker?ForwardPage=az/cds/en_us/0900823d/80/13/c0/3c/0900823d8013c03c.jsp .
Use carb/throttle body cleaner sprayed into the iac and throttle body. Let soak a few minuets, and run at fast idle until the smoke clears.
Usually when an engine surges up and down it means there’s an air/vacuum leak somewhere. And this could include anything from a leaking air intake hose, a leaking throttle body gasket, to a leaking intake manifold gasket.
Anyway, that’s what I’d look for.
Thanks Tester you were right!! Its my girlfriends car and once I started lookin under the hood found the problem pretty quick…and a few others that needed addressing.
There may be other people with a similar problem. What did you find?