Uneven Idle

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Apr 23, 2004 | 03:48 PM

mweeps

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Joined: Oct 2002

Posts: 348

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Uneven Idle

My Bronco is dropping RPM at idle if anything is running A/C or defroster it will die. What can I check? Clean throttle bodies? Any help would be great.

Apr 23, 2004 | 05:32 PM

CLHAY

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Joined: Nov 2003

Posts: 34

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From: Westchester County, NY

What year??? What engine??

Apr 24, 2004 | 05:00 PM

chrisbeery

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Joined: Dec 2000

Posts: 100

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From: Sacramento, CA

Me too.
1989 Bronco 302 Auto

My engine dies when A/C on and I let off the throttle. Also idle “hunts” sometimes (goes from 600-100) up and down while cold. I know theres a sensor to kick up the idle when the A/C is on. What’s it called, and where is it, and will changing it require depressurizing the system?

Thanks

Apr 24, 2004 | 06:49 PM

CLHAY

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Joined: Nov 2003

Posts: 34

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From: Westchester County, NY

Check for vacuum leaks and test IAC.

Apr 30, 2004 | 10:15 AM

mweeps

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Joined: Oct 2002

Posts: 348

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96 with 351 I hate how this new forum doesn't show my sig. I was beginning to think it may be vacuum leak. I need to check for one before I pay the money out for EGR Valve and EGR position sensor.

Apr 30, 2004 | 12:04 PM

broncobillybob

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Joined: Sep 2003

Posts: 1,276

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From: Auburn/ Opelika

IAC, TPS, exhast leak and EGR seem to the culprits people come up with. I've replaced my IAC and it still idles high sometimes. The other day I cruised around in a parking lot at a steady 10 mph with my foot off the gas like it was in cruise control but it wasn't. We'll see I guess. -BBB

Apr 30, 2004 | 05:11 PM

CLHAY

Freshman User

Joined: Nov 2003

Posts: 34

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From: Westchester County, NY

Damn TPS!!!!!!!!! If not a vac. issue, it's likely an IAC and/or TPS problem. Check them both and replace as needed!!! I hate idle hunting

CLHAY!

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May 1, 2004 | 05:26 PM

Trublufords

Senior User

Joined: Apr 2004

Posts: 443

Likes: 1

From: Central Va.

We used to do a lot of upper plenum gaskets (intake) for high idle but hunting and low idle could be wrong pvc valve or iac (try tapping on) dirty throttle body(get spray can carb cleaner,prop throttle body open , spray wipe - scrubb with toothbrush then fire up will not fire right away, then get a buddy in Bronco with it running and spray in t body- stab hard when it tries to stall repeat- repeat again ) we see this condition a lot after battery has been disconnected. To you with a 96 , did away with egr pos sensor went to presure feedback setup. unless very early build date. (PS ignor DO NOT CLEAN THROTTLE BODY labels) Our Ford Training classes instructors have been telling this since 85