89 F-150 IDLES at 1,700 RPM...HELP - Ford Forums

04-28-2001, 12:38

I would like to know if anyone would happen to know what would B causing my 1989 F-150 (with 5.0 5 speed EFI and all bone stock) to idle at between 1,500 and 1,700 RPM? It's driving me crazy and I'll wear out my clutch in no time! I've tried unplugging various things to no avail.....any suggestion would greatly B appreciated. If you know of a part I need to check out, please describe what and where it is. Thanks

Richard

04-30-2001, 19:29

I can't believe what the problem turned out 2 B! Was the plenum gasket (gasket between upper and lower intake manifolds); there wasn't much left of it ; can't believe the truck even ran at all. I guess U can thank the Ford computer. My F-150 4X4 ( the one I just took the upper intake off ) had a terrible idle problem. The truck is an '89 ( with 302 & 5-speed) and I've had it since '92. The truck would never idle below about 1,100 RPM when I first purchased it. Over the years it became progressively worse. It got 2 the point that it would not run below 1,700 just this past weekend. I couldn't stand it any more...as this would wear out my original clutch! This truck has 136,000 miles on it now; had 46,000 when I bought it back in '92. I just finished cleaning and getting everything perfect and reassembled with new gasket & sealer better than the factory. The truck runs better now than it ever has since I owned it!!! I can actually adjust the idle where I want-800-850 RPM! Wow what a difference! I just can't believe it! And 2 think, I posted the "high revving idle" question on every board know 2 man and no-one guessed it!.hehehe I'm tickled! Am I tooting my own horn?....forgive me board. Thanks guys 4 all your replies.
:D

Rich