idle control problem

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Jun 29, 2009 | 06:44 PM

john luke

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idle control problem

Over the past couple of weeks, I have had several instances where, either when slowing to stop or making a slow turn, rpm's dropped to zero and the engine quit. It reminded me of a problem I had with my 98 f150 where the idle control solenoid giave out. My son had the same problem on his Dodge. this truck does not have that device. Today my check engine light came on and Auto Zone read a PO506 code. The probable causes: a. Vacuum leak (couldnt find one). b. dirty throttle body (manual clearly says, do NOT use carb cleaner here, what do I use?). c. IAC motor defective or poor connector to IAC valve. My Haynes manual doesn't even show a IAC valve. Anybody have an educated guess on this?

Jun 29, 2009 | 07:00 PM

Greg B

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According to the list of codes I have it states that "idle cntrl sys rpm lower than expected". I would check out an emissions and powertrain control shop manual from your local library if they have one and follow the diagnostic routine provided for that code. There are many things that could cause the problem. Vacuum leak would be one of the many possible causes. I use throttle body and mass air flow sensor cleaner for cleaning throttle bodies on Fords. Possibly someone on here can give you more direction than I have, but that's usually what I do when I'm "flying blind" on a problem on these vehicles. It's kind of time consuming, but it hasn't failed to get me to the cause of a problem yet and I always learn a little more about the engine management system each time I have to go that route.