my 1986 IROC loves to idle very high (around 1000-1200) most of the time...
i've tried all the idle controls and nothing will set it lower. gimme some suggestions.

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there's no replacement for displacement

 

1000-1200 is normal idle when its not in gear ... as far as I know anyway

idle is much easier to work with on a carb most times (I forgot how to do it on one of them friggen TPI whatsits )

 

the thing is though, when i put it in to gear, it slams down the tranny cause it revs so high, and its not the tranny mounts cause they are fine...

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there's no replacement for displacement

 

Have you tried adjusting the Idle Air Control (IAC) valve (I'm assuming you have TPI?) If not, there is a tech article on how to do this in the tech section. I had a problem with my '85 Z28 idling too slow and dying at stops or when shifted into reverse. An IAC adjustment fixed the problem.

A vacume (I can't spell ) leak could also cause higher than normal revving. I could make my '85 do this by disconnecting the PCV valve from the hose connected to the intake manifold.
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'91 Camaro RS


Bin Laden can have my Camaro when he prys it from my cold, lifeless hands!

[This message has been edited by RSFreak (edited December 11, 2001).]

 

tranny mounts can look fine until you replace them... unless you've actually dropped the tranny to look, you can't be 100% sure...

if Amorget was still posting he'd tell you about his experience

 

i've tried the idle valve, and that didn't work so i went and picked up a mount and will try that now.

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there's no replacement for displacement

 

I agree. Yes, when your engine is cold the idle will be high, but if the engine is fully warmed it should be 600-700 rpm (depending on your engine which you haven't mentioned). I had a friend who recently had the same problem with a TBI. Turned out the gasket went bad and caused a leak.

Another problem could by your CTS (Coolant Temperature Sensor). If it is not working properly it could be telling the ECM your engine coolant is cooler than it really is and cause the ECM to think it is in "Start Up" mode.

Lastly, a bad MAP sensor (if you have SD TPI or TBI) can also cause havoc with your idle.

But I need more information about your engine and year of car to offer any more advice.

 

well..... its a 86' IROC 305 TPI. i replaced the mounts and that did nothing at all. im gonna get a can a carb cleaner and spray around the engine bay looking for leaks and changes in idle. its a cheaper wway to start then replaceing sensors.

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there's no replacement for displacement
1986 IROC 5.OL auto w/posi

 

I wouldn't expect changing mounts to do anything for the idle. Make make the car feel smoother though or stop an annoying squeak but nothing for the high idle problem.

Vacuum leak is my first hunch. I wouldn't go replacing sensors until you have someone put a scan tool on it - to read whatever codes the ECM is throwing and to see how the readings of the sensors. Codes by themselves (without sensor readings) can be misleading. Often a "flaky" sensor may not actually show a "failure" but cause other sensors (while the ECM goes into "Safe Mode") with show a "failure" in reaction to the ECM trying to keep the engine running.

 

it reads codes 42 and 54. ive heard 54 can be alot of things.

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there's no replacement for displacement
1986 IROC 5.OL auto w/posi

 

Code 54 is your Fuel Pump Circuit. I think you are confusing it with Code 52 (ECM/Memcal error). Code 42 is generally caused by a bad Ignition Module.

Both (fuel pump and ignition module) are common problems.