high idle help
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Senior User
Joined: Jul 2010
Posts: 156
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From: Wasilla Alaska
high idle help
1990 f250 with a 5.8L from a 95. so its idling at like 1500 but it will slowly idle down over like 2 or 3 minutes. obviously this aint right. with the idle air controller unplugged it will idle lower but just a little choppy. at lower rpms when accelerating it will jump a little under load.
ive gone through a few spare iac's that werent new but didnt make any difference.
snap on scanner gave no codes with or without the iac plugged in.
runs great with the peddle down...!
any ideas??? thanks
ive gone through a few spare iac's that werent new but didnt make any difference.
snap on scanner gave no codes with or without the iac plugged in.
runs great with the peddle down...!
any ideas??? thanks
Post Fiend
Joined: Jan 2005
Posts: 8,402
Likes: 10
Ford Fuel Injection » Throttle Position Sensor (TPS) Check out the items listed on left of the page in this link and also do electrical tests on TPS as described.
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Senior User
Joined: Jul 2010
Posts: 156
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From: Wasilla Alaska
yeah the tps was bad and i replaced it. this problem is with the new tps in place. new tps helped other problems but this is my last little gremlin. other than the idle it runs perfectly.
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Senior User
Joined: Jul 2010
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From: Wasilla Alaska
i guess its possible. i did smoke it and found NOTHING. it doesnt rev or anything and idles down quickly with the iac disconnected. is there a way to take the iac apart to clean it? all the ones i had on there were probably dirty.
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Senior User
Joined: Jul 2010
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From: Wasilla Alaska
i sprayed about a half a can in it! are they sensitive to being dirty? would a little dirtiness make it perform that bad? it seems to move back and forth in there pretty freely...
im just thinkin theres gotta be something else causing the iac not to function properly. would a bad o2 sensor tell the computer to open up the iac? i was also thinking a bad temp sender would make the computer think the truck is cold all the time and keep the iac open.
im just thinkin theres gotta be something else causing the iac not to function properly. would a bad o2 sensor tell the computer to open up the iac? i was also thinking a bad temp sender would make the computer think the truck is cold all the time and keep the iac open.
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Hotshot
Joined: Sep 2001
Posts: 11,958
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You can just take the IAC off and spray carb or TB cleaner in it. Then after its clean, you can spray a little PB Blaster in it to lubricate it. This usually works, but when an IAC valve is in that condition, I find that it usually works better to just replace it. You can get a new IAC gasket for 2 dollars, which I would do it you clean it.
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