cannot get idle down

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Mar 17, 2006 | 10:07 PM

my72ford

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From: YORK S.C.

cannot get idle down

i have a 86 bII 2.9 i have replaced the iac switch,now it idles smoothly at 1,100 but it is supposed to be 850 with a manual trans..the repair manual says it's computer controlled.is there something else i can do? i have ckd all the vacuum lines,replaced the egr valve last week.just cannot understand why it's idling so high,any help is greatly appreciated!

Mar 18, 2006 | 07:54 AM

frankenbroncoII

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From: north carolina

have u checked the tps. its the lil black senser on the side of the throttle body. it reads the movement of the butterfly and tells the puter how much "gas" your giving it. if this thing goes bad it could be telling the puter wrong info and the puter is either making it run rich, or lean. i have had them go bad b4 and had it go both ways. high idle and poor road running, and or had to hold it to the floor just to get it to crank and as soon as u took your foot off the pedal it would stall.

Mar 18, 2006 | 08:10 PM

Ken00

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From: South Jersey

What happens if you pull the connector off the IAC?

Pullling the codes might find something, don't forget the KOER test.

Mar 18, 2006 | 08:22 PM

my72ford

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From: YORK S.C.

i pulled codes today,nothing came up about the idle...only code number 41.i pulled plug off iac while engine was running and it stalled

Mar 18, 2006 | 08:37 PM

Ken00

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From: South Jersey

Did the ECU control the rpms OK when you ran the KOER test?

I'm suspecting a vacuum leak, I would check again, how about the IAC gasket.

Mar 19, 2006 | 07:14 AM

my72ford

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From: YORK S.C.

code number 12 did show up the iac valves and gasket is brand new i replaced that last weekend i have ckd all the vacuum lines twice,where is the tps located?

Mar 19, 2006 | 07:20 AM

frankenbroncoII

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From: north carolina

on the side of the throttle body oppisite of the throttle linkage. its black, has a plug and 2 screws on it. and the butterly has a peice that sticks into it so the senser can read how much it opens/closes.