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Discussion Starter · #1 ·
my 96 SS has had a bit of a rough idle since I bought it this spring. So far I have changed fuel filter, egr valve/solenoid, pcv valve and now have new plugs in it. It seems to jump around between 600rpm and 900rpm while stopped. Driving there are zero issues and it is not throwing the CEL. AM I just being too d#$m picky or is there another part I should check into.
 

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IAC - idle air control. Clean, if that doesn't work, replace.
 

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Discussion Starter · #3 ·
thanks for the quick reply. I will check the manual and find out where that part is this weekend. Hopefully not an expensive part.
 

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thanks for the quick reply. I will check the manual and find out where that part is this weekend. Hopefully not an expensive part.
Pages 6E3-C2-13,14,15. Also 6E3-C2-4 and 6E3 -C2-24. This is for 1994, 96 should be the same or near. As noted, don't just dump the whole part in solvent.
 

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I would plug the car into a live data scan tool or laptop and check the IAC counts before deeming that the part is bad. the FSM states what #s are acceptable. I dont have the data off the top of my head if needed I can find it.
 

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Discussion Starter · #7 ·
So after checking on the prices of a new one I decided I better make sure that it is bad before replacing. What is the best way to go about cleaning the IAC. I should have been more clear, I only own a crappy haynes manual right now. Still need to get the GM ones. I will try the reset procedure and if that does not work I will try and get my buddy over here to read it with his meter or my cousin to check with a live data scan tool.
 

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So after checking on the prices of a new one I decided I better make sure that it is bad before replacing. What is the best way to go about cleaning the IAC. I should have been more clear, I only own a crappy haynes manual right now. Still need to get the GM ones. I will try the reset procedure and if that does not work I will try and get my buddy over here to read it with his meter or my cousin to check with a live data scan tool.
Just posted today: http://www.impalasuperstore.com/naisso/Forum2009/topic.asp?TOPIC_ID=48005
 

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another 'free" test is start the car with no ac on. at idle turn the wheel all the way over and turn on ac at the same time. if your IAC is working well there should be no bogging of the motor or drop in idle like it stumbles. If is is basically seamless than that would indicate the IAC is responding within tolerances.

You certainly can clean it if service is unknown or it and the TB have not been cleaned.

My $02 would be buy a TB gasket and can of TB cleaner pull the TB and do this on the bench.

The link about taking the IAC apart....well go fo it but in the FSM it is clear NOT to depress the printle.....no doubt because striping the drive gears results. As that link states you really need to be carefull if pulling the IAC apart.
 

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Discussion Starter · #10 ·
I would plug the car into a live data scan tool or laptop and check the IAC counts before deeming that the part is bad. the FSM states what #s are acceptable. I dont have the data off the top of my head if needed I can find it.
Ghetto Wagon can you get me those numbers. My cousin is bringing his live data scanner tomorrow so we can check it out. Also going to check around on the net to see if I can find a better price online. Thanks guys. Great info!
 

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Discussion Starter · #11 ·
I have not had time to check anything yet but I did notice the car idles smooth until warmed up. Not sure if this changes the direction of what I should be checking or not.
 

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Ghetto Wagon can you get me those numbers. My cousin is bringing his live data scanner tomorrow so we can check it out. Also going to check around on the net to see if I can find a better price online. Thanks guys. Great info!

Sorry for the Delay, Been busy cleaning out the house!

From my 95 Factory manual it says IAC counts should be anywhere from 5-50 at idle And the Learned IAC should also be 5-50

The Lower the COUNTs the higher the idle. The HIGHER the counts, The lower the idle is. That should make some sense depending how high or low the idle speed is. Live data on a scan tool should state RPM as well.

FSM says to check the IAC for any debris, Remove and clean. Also check PCV operation if counts are not within spec.
 

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Discussion Starter · #14 ·
would an IAC out of a Roadamaster LT1 be the same as my 96 SS? I know of one at the local JY and was thinking about pulling it and cleaning it so I would have a spare in case I screwed up mine.
 

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Discussion Starter · #16 ·
sweet! Now just need to get off work early enough to get down there before they close. Thanks Mike for all the help. Love the paint job on your car!
 

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Discussion Starter · #18 ·
Ok, finally getting around to this problem. Could never get my lazy cousin to check the IAC numbers for me. I found some of Ebay and changed it out with a new one. I reset the IAC after installing the new one. Now I have a different problem. Car idles high. Around 2K RPM in park and about 1K RPM in a gear. Now after having this problem I dug up this old thread and reread the whole thing. The link 94MI9C1 posted about resetting also stated that you can move the new pintle to match the position of the old pintle. I noticed when installing the the new one was further in then the old but I had not read that part of the link before installing. I ASSumed once plugged in it would move to where it needed to be. Now I am thinking I probably need to remove the new one and back out the pintle to match the location on the old one. Wanted to check what you guys think about this before I tear it apart again. Also thinking about taking BALLSS advice and getting new gaskets and pulling off the TB and cleaning it all on the bench. Is there anything I need to be carefull with doing that? I already have the TB bypass mod so I will not have any coolant to deal with. Thanks again guys.
 

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The IAC will set itself into the proper position if all is working correctly. The idle will be high when you first start that car. It should slowly settle to the correct idle within the first minute of running.
 

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I had a problem a couple years ago when I touched my IAC. Found out the tps was screwing up. Be sure to check wiring to it before replacement. The wires broke off inside the insulation on mine after tps replacement :(
 
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