1999 Chrysler LHS Idles eratically up and down ,,

1999 CHRYSLER LHS
135,000 MILES • 3.5L • 6 CYL • FWD • AUTOMATIC
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STELLA94
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  • 1 POST
Whether we start the car and it is cold or warm the engine wants to idle up and down from 600rpm at normal rest up to 1300 then back down ,, will also do this while at a red light ,,,,,in or out of gear,,,,,
No codes and we had the spark plugs replaced again to try and help but no luck ,,,,, no codes so what now.....?????????????
Feb 17, 2014 at 6:13 AM
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WRENCHTECH
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  • 20,761 POSTS
First eliminate all vacuum or air leaks in the system. You may have a bad IAC ( idle air control) but try cleaning the throttle body first. Remove the intake snorkel, have someone hold the throttle wide open for you and scrub the back side of the throttle plate and surrounding bore with an old tooth brush and some carb cleaner. Be sure to spray some into the small holes next to the throttle plate. That should help stabilize the idle. If it still has a problem, replace the IAC.
Feb 17, 2014 at 6:48 AM