How to clean your IAC (Idle Air Controller) valve

Chris said:
You’re very welcome!
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Issue is back, bought a new one and same result. I will confess I did NOT clean the square housing that it sits on, could this be why worked for like a week then bam same issue even with a new IAC? Now it barely runs when going at 35mph have to keep goosing it to keep it running. Thinking fuel pump honestly at this point.
 
johny_knoxville said:
Issue is back, bought a new one and same result. I will confess I did NOT clean the square housing that it sits on, could this be why worked for like a week then bam same issue even with a new IAC? Now it barely runs when going at 35mph have to keep goosing it to keep it running. Thinking fuel pump honestly at this point.
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You may want to start a new thread about this. It’s going to get lost in this thread and not get the more helpful responses.
 
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johny_knoxville said:
Issue is back, bought a new one and same result. I will confess I did NOT clean the square housing that it sits on, could this be why worked for like a week then bam same issue even with a new IAC? Now it barely runs when going at 35mph have to keep goosing it to keep it running. Thinking fuel pump honestly at this point.
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If it's the original fuel pump, it's probably time. I think bought mine I think through Amazon just last summer - am pretty sure it was a Bosch which is what most people highly recommend.

But you probably really need to see if it's spitting out any codes. If you dont have a scanner, the simplest way to quickly get codes is to put the key in the ignition and turn to "On", then "Off", then "On", then "Off", then "On" and leave on. The codes will come up in the odometer.

Depending on what codes you get, you might also try spraying carberator, brake cleaner, WD-40, Chemtool, or anything similar onto the mating surfaces of the IAC with the engine running. If the engine smooths out after spraying a particular place, then you've found the problem.
 
Jerry Bransford said:
Yes there is a gasket between the throttle body and intake manifold. And yes the IAC will have an o-ring on it.

That said, I don't believe there's any need or benefit to removing the throttle body to clean the IAC. And seldom does the IAC actually need to be removed from the throttle body to clean it very effectively. I feed TB cleaner into the TB while the engine is idling and the IAC will draw the TB cleaner in through itself, cleaning itself in the process. It will not suck the TB cleaner in unless the engine is idling, so don't rev the engine during the cleaning process. The engine will die repeatedly during this process since the cleaner is flooding the inside of the IAC but that's fine and actually good, it gives the cleaner more time to clean. Just restart the engine after it dies.

I try to use a third of the can cleaning the IAC at idle RPMs, then finish the can by spraying the inside of the TB while revving the engine a bit. Every so often I'll let it idle and spray more cleaner at the passage inlet slot the IAC draws its air through, just to make sure the IAC is perfectly clean.

The IAC's air passage inlet is just above the throttle body's valve plate in this illustration...

View attachment 14111
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I have a 2006 sport, 4.0L with the updated IAC (2005-2006).
Do you know if this method will work or would I need to remove the throttle body and IAC to clean like @AussieShane did?
 
I have a ‘97 sport 4.0 with just under 100k. I figured I should change the spark plugs because I don’t think they’d ever been changed. I also figured I should clean out the IAC while I was there and sprayed throttle body cleaner in the throttle during idle and while I had someone hit the accelerator. I drove it around for a while afterwards and it was the smoothest I’ve ever felt my TJ run, I could hardly feel vibration at a stop.

This morning I went to start it and it doesn’t start unless I hold the gas down. If I let go immediately it’ll stall. Did I mess something up or will this go away with more driving?
 
Andresme said:
I have a ‘97 sport 4.0 with just under 100k. I figured I should change the spark plugs because I don’t think they’d ever been changed. I also figured I should clean out the IAC while I was there and sprayed throttle body cleaner in the throttle during idle and while I had someone hit the accelerator. I drove it around for a while afterwards and it was the smoothest I’ve ever felt my TJ run, I could hardly feel vibration at a stop.

This morning I went to start it and it doesn’t start unless I hold the gas down. If I let go immediately it’ll stall. Did I mess something up or will this go away with more driving?
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I did some reading on this and apparently the computer learns how much air is needed over time and to reset that all you need to do is disconnect the negative terminal for a few minutes and reconnect it later. I did this and it solved it if anyone ever runs into the same problem in the future!
 
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Hey guys. Trying to clean my IAC, but mine looks different than the pics in the OP. And only one torx screw holding it in. Anyone else run into this?
 
Just mentioning (out of experience) be careful once you take the housing off, there is a gasket (very thin) and if you touch it, or move it, if the housing has never been removed before, you will break it. Then you will have to do a search on google to see how to make a new gasket from a cereal box. :)
 
Chris said:
If you're experiencing idle issues on your Jeep Wrangler TJ the most likely culprit (and the first thing you should check) is your IAC (Idle Air Controller). Often times the IAC gets very gunked up causing the Jeep to idle improperly. A simple cleaning is usually all it takes to get it running as good as new.

If you end up needing to replace your IAC valve (they do fail on occasion), you can find the part numbers (and the links to purchase them on Amazon) below:

2005-2006 IAC Valve (Part # 4861552AC)
1997-2004 IAC Valve (Part # 4874373AB)

There is no need at all to remove the throttle body to clean the IAC. This is probably one of the easiest and cheapest things you can do.

Below you'll see a diagram of the top of your throttle body with the IAC sensor labeled.

View attachment 14140

Take your IAC off (it's held on by two small torx screws). Clean it with your throttle body cleaner, this is what it will look like before and after.

View attachment 1798

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Then take off the IAC housing and both sides (house and throttle body). clean that too. before and after...

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Put it all back together and you're good to go. Very, very simple. It doesn't get any easier than this!
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Chris did you make your own new gasket for the iac body or pick one up?
 
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Head Lice said:
No 'Check Engine' light ...
No codes ....

The 'surging' happens in 1st and 2nd gear ..... at low speed. Will be idling down the road in 1st, and when the throttle is barely touched, it will surge ahead. Very aggravating. Tried this procedure on a steeper adverse (under load) and it was less apparent. On another forum, it was suggested that a throttle return spring may help.
Ideas ?
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Hi, did you managed to solve this problem? I have the exact problem. Many thanks!
 
Swimmer35 said:
Well, I've had this issue off and on for awhile. I've ordered a new IAC and TPS sensor, but then I saw this write up. I took everything apart and cleaned everything per these instructions, but I still have the issue. Hopefully when the new sensor gets here, that'll fix it.

Just in case, is there anything else it could be?
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[For reference only] since this thread is 6 years old. I'd check for damaged wiring connector or corrosion in electrical plug itself. Obviously could be a couple other things. Have a 97 model 2.5. Cleaned but did the same after. IAC wires were rubbing against metal bracket & wires were broken. IAC wasn't opening and closing properly. No current. Cold IAC was mostly closed. As it Warmed up IAC shifted to high idle. The gunk had it sticking in both positions. Either extremely high idle(hot) or no idle.(cold). Does this make sense ?
 
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