Mechanics

F250 5.8L IDLE IS ALL OVER THE PLACE

1989 Ford F-250

Engine Performance problem
1989 Ford F250 V8 Four Wheel Drive Manual 147000 miles

Hi guys, I have a 1989 5.8L and the idle is all over the place. I did a major tuneup, changed TPS, AIC and it stiil has the same problem. When at idle, (no load), the engine just will not idle at one speed. The RPMs are always moving up or down, 800 to 1300 to 900 to 1200 to 900 you get the idea. It will not stay at one RPM for more than a second or two. Can some one please steer me in the right direction? PLEASE? I am at a loss as to what it might be. Any help would be appreciated. I asked for help earlier and was recommended to change TPS and AIC which I did. Thanks for any help.
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DAMIEN256
January 25, 2009.




When was the last tune-up?

Check engine compression, PCV and EGR valves, Vacuum leaks
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Tiny
Rasmataz
Jan 26, 2009.
3 days ago I finished a major tuneup on it. There are vacuum hoses all over the place. Is there an easy way to check for vacuum leaks?

Tiny
DAMIEN256
Jan 26, 2009.
Use WD40 and spray into the areas of the intake manifold/base of throttle body/vacuum hoses when the idle smooths out you've found the leak or use a stethoscope to track the leak by the hissing noises, or the propane and scantool method

Tiny
Rasmataz
Jan 27, 2009.

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