Erratic idle

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Mar 24, 2009 | 09:49 PM

Zero Obliquity

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Erratic idle

I have an 88 F150 w/302 and a 5speed. When I come to a stop, about 50% of the time, the truck will idle high by about 200rpms. If I blip the throttle it will drop back to the normal idle speed. I know it is not the throttle cable sticking. If I coast forward in gear, without touching the throttle, and go above 1000rpms, and push in on the clutch, the idle will remain high till I kick it down. Any ideas? Thanks for any help in advance.

Mar 24, 2009 | 10:53 PM

393STROKER

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From: houston

intake/vacuum leak?

Mar 25, 2009 | 12:05 AM

DasCheckers

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From: Four Corners, MT

Does it pull any codes?

Mar 25, 2009 | 12:16 AM

nighthawk285

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From: La Grande, OR

sticky TPS/IAC?

My truck also does this every once in awhile while its in the "learning" mode after its been disconnected from the battery, and then sometimes when I'm out wheelin, but if this is a constant thing, try pullin the codes and see what it says...

If you need to know how, this site'll show ya!
Ford Fuel Injection How To Run a Self-Test

May 9, 2009 | 10:44 PM

Highrollerace

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I ran codes, cheak for vaccume leaks, etc,etc! End up being the rod that the butterflies are attach to at the throttle body. Was backing out of the drive today, idle was fine. Put her in gear and let out the clutch push in the clutch, high idle again. Put it in neutral and popped the hood and there was a very small gap between the set screw and the flange for the idle. Shut the truck off and when I would turn it by hand I could barely feel it catch. The plate on top of the rod isn,t removable as far as I can tell. Kind of afraid of making it worse if I mess with it. Must be a burr or wear spot on the rod or in the hole. Any ideas on fixing this!!

Just another thing to check!!

Thanks, Dennis

May 13, 2009 | 06:19 AM

nighthawk285

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From: La Grande, OR

New TB? I don't really know if those throttle bodies are rebuildable.....

May 14, 2009 | 11:09 AM

Highrollerace

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Hey all!! Put a stronger return spring on and solved the idle problem. Is a little stiffer but I'll get use to that. Just glad I happened to get out and check for that. Would not hang up when I did it by hand. Guess the throttle cable placed it on a different bind.

Thanks for the replies, Dennis