High Idle

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Feb 21, 2001 | 11:29 PM

godunlop

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High Idle

My 90 Bronco,302, AOD idles at 1200rpm +. I've replaced the MAP sensor, TPS sensor, Idle Air Control Valve. The computer codes are all 1's. The truck started running a little rough when this idle problem started. I'm thinking the computer is bad. Any ideas anyone. I'd appreciate any help I can get.
Burning up brakes in Texas.
Gerald

Feb 22, 2001 | 07:35 PM

thelonerangerxlt

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High Idle

Gerald, before you change computer, try cleaning out throttle body (specifically around the butterfly and edge of butterfly). Carbon buildup in this area sometimes causes a poor idle. Also, disconnect battery for about 20 minutes, and leave a door open. This resets the computer. Good luck. Don

"Nothing lasts forever except natural stone and old Ford trucks." (Willie Nelson)

Feb 22, 2001 | 09:39 PM

godunlop

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High Idle

Don,
I cleaned the throttle body and butterflies. I also reset the computer. Unfortunately nothing changed. Thanks for the info and guidance. It's greatly appreciated.
Gerald

Feb 23, 2001 | 06:00 AM

AlM

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High Idle

could be a vacuum leak..esp at the throttle body.
are you thinking the codes are for "system ok"?

Feb 26, 2001 | 04:42 PM

godunlop

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Thanks AIM,

I did another extensive check of the induction system and found a leak in the lower plenum.

Thanks again,
Gerald

Mar 6, 2001 | 09:46 AM

smackitup

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High Idle

Also, look at your little Idle "motor" it's on the right side of the throttlebody, and has a solenoid attached to it, if you unplug the solenoid, i bet your idle goes down, you may have to clean/replace it, mine went bad, so I just left mine unplugged and brought the idle to the right speed using the little set-screw just like you would a Carb, works great now, my "idle motor" was getting really jacked up, it must have been wide open for a while and it started all the sudden my bronco would (after taking it OUT of gear) would go all the way up to 2K Rpm, i unplugged the solenoid, and bam, right where it needs to be.

P.s. I removed mine and cleaned it out, it had ZERO effect

Mar 6, 2001 | 12:09 PM

godunlop

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High Idle

Thanks for the info C. I did try unplugging the solenoid before, and the idle did not change. I was thinking the same as you. I did discover a leak at the manifold. Working on it now. Thanks again and I'll keep the idle solenoid in mind for future reference.
Gerald