2000 Ford Expedition Idle

2000 FORD EXPEDITION
105,099 MILES • V8 • 4WD • AUTOMATIC
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TJBOPP
  • MEMBER
  • 1 POST
While sitting at Idle the engine will repeatedly rev up to 1000-rpm then down to 500-rpm. The engine runs fine other wise. Help?
Mar 16, 2009 at 2:26 PM
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MERLIN2021
  • CAR REPAIR CONTRIBUTOR
  • 17,250 POSTS
Check the IAC(Idle air control) valve, it's bolted to the throttlebody, turn the truck off, disconnect the air duct, grab a rag, clean out the throttlebody with TBI cleaner and look for cracks in the air duct and vacuum leaks.


https://images.2carpros.com/forum/automotive_pictures/62217_CRC_Throttle_Body_19.jpg

get a can of spray throttle body cleaner, spray the vac lines and maniflod area, when the idle changes, youve found the leak! You want the engine running and spray on the outside but do direct the stream onto the hoses, if it is a vacuum leak, the engine idle will change speed, then you have detected a leak, repair the vacuum leak and see how it runs! If that doesnt do it, you may need a new idle air control valve, it's bolted to the throttlebody.
Mar 16, 2009 at 2:38 PM
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