high idle and other stuff....
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From: Lupton, Mi
high idle and other stuff....
I have a 1988 F150 XLT Larriat with a 302 5.0 EFI and a 3 speed auto. My check engine lgiht was on so I did the test i found here to pull the codes... they were EGR stuck open, TPS voltage too low, TPS voltage too high. I cleaned my egr, no difference. Truck would still idle high. So I unpluged the TPS and the truck idle ok, bit low but it was useable. Today I got a new TPS, and installed it. Truck idled great. Took it for a spin throught the back roads and about about 20 miles the high idle was back, but this time with no check engine light.
Any ideas? When I changed the TPS I pulled the throdal off and cleaned it out, and clean the the other thing to the right... the Idle air something or other thing... lol. I used all new gaskets. I know my plennum gasket is good cause I can spray the bottom of it with carb cleaner and it does not idle down... a trick I was shown a long time ago on a carb 302...
I have the battery unhocked tonight to clear the computer and codes.
Thanks.
Jim
Any ideas? When I changed the TPS I pulled the throdal off and cleaned it out, and clean the the other thing to the right... the Idle air something or other thing... lol. I used all new gaskets. I know my plennum gasket is good cause I can spray the bottom of it with carb cleaner and it does not idle down... a trick I was shown a long time ago on a carb 302...
I have the battery unhocked tonight to clear the computer and codes.
Thanks.
Jim
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From: Easton,Ks
Pull the plug off the IAC and see if the idle goes down, if the idle does not go down it is more than likely a bad IAC valve.
But this should have show up when you ran the KOER self test.
You should get a "Self test could not control idle" error.
Did run the KOER self test?
Not a good idea, this can set memory codes and cause other problems.
Clear them the right way like the book says.
the other thing to the right... the Idle air something or other thing = IAC
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From: South Florida
Might want to check for vacuum leaks. I had a 91 explorer that was giving me a high idle. All the vacuum lines looked good under the hood, so I replaced the IAC valve, but I still had the high idle. A few days later I was underneath the truck and found a vacuum line that connected to the transmission had separated. I never saw or heard anything that would indicate a vacuum leak when I was poking around under the hood because the leak was so far away.
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From: Lupton, Mi
well, I drove it down state to detroit today and it was fine. I did unplug the valve and the truck died instantlly. I think the truck is idleing normally cuase my ma's 2001 winstar with a 3.8 I think idles high but ford dealer says its ok.... I'm used to chevys.... so I'm a newbie in the ford world.
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From: Lupton, Mi
well, with my truck I'd say it prolly around 1100-1200rpm just by guessing, I don't have a tack on it, yet. My temp gauge does not work, so I'm thinking I may need a collant temp sensor. But then if it was bad wouldn't the check engine lgiht be on?
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From: Easton,Ks
If your engine temp sender (one wire) is bad the gauge may not work but it is not wired to the computer at all so no you would not get a check engine light.
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From: Lupton, Mi
ah, ok. so the engine coolant temp sensor will throw an engine light? I was thinking it may be bad and the truck is idling a bit high trying to "warm" it up....
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