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:( Recently, I took out the throttle body in my 87 Coupe to clean it up. I used 2 spray cans of carburetor cleaner, lots of rags and a toothbrush. The Idle Air Control valve was removed and cleaned. Everything was sparkling clean when reinstalled in the car. I followed the instructions found at:

http://www.geocities.com/jgkov/IACService.html

All electric connectors were checked and the TPS was adjusted to 0.54Vdc following the instructions in:

http://www.geocities.com/jgkov/TPSService.html

When cold, the car starts immediately, revs to about 800 rpms for a few seconds and drops to 500-600 rpms, which is fine. After warm-up and driving for a few minutes, when I stop at a traffic light or whatever, I shift into neutral and find that the idle is 1,200-1,400 rpms, which is too high. Then I "blip" the accelerator pedal and the rpms drop to 500-600. I even sprayed a bit of WD-40 in the throttle linkage to see if the problem was due to a sticking linkage but the problem persists.

I tried to pull codes using a jumper from terminals A & B in the ALDL and there are no codes. This method was found at:

http://www.c4vettes.com/ecm.htm

The MAF sensor and both relays were installed 2 years ago. The engine has no internal mods, only a KN filter with cut lid, throttle body airfoil, by passed coolant in the TB, Bosch 4+ spark plugs.

This high idle makes my engine run hotter and everytime I get stuck in traffic, I have to shift into neutral to "blip" the pedal and bring the revs down, which is a PITA.

Any suggestions?:whip:
 

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Official Forklift Driver
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I had that same problem a while back, like the throttle was stuck. I'd blip the throttle and the idle goes down. I took it off the engine and cleaned it inside and out. I didn't do anything else to it and it hasn't stuck on me yet.

There is one step missing from that instruction page. Before you put the IAC back in after you clean, you have to measure it.

*Measure from the seat where the gasket sits to the tip of the pintle on the IAC. It should not exceed 1 and 1/8".

If it was extended beyond that when you put it in the IAC could get ruined.
 

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I did the same thing to mine a couple years ago. After cleaning I still had the same problem. Replaced the IAC, have'nt had any problem since. :)
 

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Once again, "Hawaiian Punch"
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1,265 Posts
AlfonsoGomez said:
:( Recently, I took out the throttle body in my 87 Coupe to clean it up. I used 2 spray cans of carburetor cleaner, lots of rags and a toothbrush. The Idle Air Control valve was removed and cleaned. Everything was sparkling clean when reinstalled in the car. I followed the instructions found at:

http://www.geocities.com/jgkov/IACService.html

All electric connectors were checked and the TPS was adjusted to 0.54Vdc following the instructions in:

http://www.geocities.com/jgkov/TPSService.html

When cold, the car starts immediately, revs to about 800 rpms for a few seconds and drops to 500-600 rpms, which is fine. After warm-up and driving for a few minutes, when I stop at a traffic light or whatever, I shift into neutral and find that the idle is 1,200-1,400 rpms, which is too high. Then I "blip" the accelerator pedal and the rpms drop to 500-600. I even sprayed a bit of WD-40 in the throttle linkage to see if the problem was due to a sticking linkage but the problem persists.

I tried to pull codes using a jumper from terminals A & B in the ALDL and there are no codes. This method was found at:

http://www.c4vettes.com/ecm.htm

The MAF sensor and both relays were installed 2 years ago. The engine has no internal mods, only a KN filter with cut lid, throttle body airfoil, by passed coolant in the TB, Bosch 4+ spark plugs.

This high idle makes my engine run hotter and everytime I get stuck in traffic, I have to shift into neutral to "blip" the pedal and bring the revs down, which is a PITA.

Any suggestions?:whip:
Heah man! check the tps again, but this time check the back of it, the part that hooks on the little lever or hook that rotates when the throttle is opened? thats what opperates the tps when throttle is opened and closed and sometimes the little lever on the tps is a little to long or if tps is tightened down to much it'll rub against the side of the throttle body causing it to stick and make the idle run high, try taking it off, and sand it down a little and put it back on to see the clearence, repeat untill it doesnt rub any more.
It might work.
 

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here is something elese to consider.. maybe the butterfly vavles are sticking part open.. maybe after cleaning it some of the gunk on the shaft was removed and there maybe slight slop on the shaft where it rides on the bushings... or maybe the throttle cable needs to be adjusted if it's a hair tight it may be sticking part open and when you tap the gas it may close enough to bring the idle down.. but then again.. if it's idleing really low.. could be the IAC motor sticking.. probably is getting tired if it's the original..

-Rick
 
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