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Double D racing

high idle 1990 F-150 v-8

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I have an old F-150 5.0 that runs good but lately the idle has gone up. I changed air filters and inline filter, but still idles a lttle bit too high. I'm afraid its going to tear up the tranny if I keep going without fixing it. any suggestions ?

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spray some starting fluid safely around the motor to see if it has a vacume leak . check brake booster forleaks it could be going bad or check valve at the booster make sure it only flows one way that is where I start at ... idle air control valve it might be worn those go bad or just dirty and sticking or plugged up port . ..and test tps sensor if it goes bad it will idle up usually 1200 on up ....check the egr ..just a few ideas good luck I am sure other have some ideas .

Edited by HiTech

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No dash light,it starts and runs fine. Just when it starts warming up the idle goes up. I watched a video earlier claiming "high idle" is caused by the TPS sensor going out...So the video made it look easy to change out... Yeah ok...

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TPS on some vehicles will also not cause a check engine light. Toyota and Chevrolet i know for sure.

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could be TPS Sensor. I had a friend with a newer ford that had the same issue. TPS sensors are usually easy to replace.

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Sometimes the light wont show up .but I have ran scans on fords and find 5 to 8 codes . also a bad temp sensor can be a problem ..the one on the intake or around the thermo stat ...in a lot of cars if that sensor is bad they can cause it to idle up as it warms up or idle erratic .but I am more pointed at the tps . check your throttle shaft too .could be worn ..

Edited by HiTech

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Just $hit can the old ford and get a chevy. Prob. Solved. Or you could hold the throttle on the floor for five seconds problem gone it won't idle high anymore, :-)

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