Jeep TJ intermittent surging idle and stalling

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mikemunz

New Member
Joined
Dec 23, 2023
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6
Location
Arizona
I’ve recently had some issues with my 2004 Jeep wrangler rubicon that I was looking for some help with. Since I purchased the vehicle, I’ve had a very loud whistling sound that I assumed to be a vacuum leak. I replaced the throttle body as that’s where a majority of the smoke came out of when testing and it has gotten better. However recently I’ve had an issue of an intermittent surging idle at startup, and stalling when coming to a stop which doesn’t always happen but happens once in a while. The whistle still happens but not as much as it did before, and only happens at idle rpm’s. If the Jeep dips under idle rpm’s the whistle goes away.

Replaced:
Throttle Body
Downstream O2 sensor 2 after check engine light
Cleaned idle air control valve

I have attached a photo of the motor and a video of said whistle/whine

Surging Idle:
https://streamable.com/954ery
Whine/Whistle:
https://streamable.com/fhmh45

IMG_3047.jpeg
 
Did you remove the IAC or clean it in place with the engine idling? Cleaning it in place while the engine idling cleans the entire IAC system, not just the IAC itself.

Also, you might think about adding a foam outer filter to go on top of your K&N's air filter's outer pre-filter layer. I ran with just the outer prefilter for a while and loads of dirt were still getting past the sock and the K&N into the air intake. I used an oiled foam Unifilter for mine though I see K&N now also has foam outer layers since they finally figured out their sock wasn't enough.

This was mine when I still ran a K&N. I still can't believe how much dirt and crap the K&N passed before I added those two additional layers over the top of it.

K&N1.JPG
 
Jerry Bransford said:
Did you remove the IAC or clean it in place with the engine idling? Cleaning it in place while the engine idling cleans the entire IAC system, not just the IAC itself.

Also, you might think about adding a foam outer filter to go on top of your K&N's air filter's outer pre-filter layer. I ran with just the outer prefilter for a while and loads of dirt were still getting past the sock and the K&N into the air intake. I used an oiled foam Unifilter for mine though I see K&N now also has foam outer layers since they finally figured out their sock wasn't enough.

This was mine when I still ran a K&N. I still can't believe how much dirt and crap the K&N passed before I added those two additional layers over the top of it.

View attachment 484673
Click to expand...

I did both. I replaced the throttle body and had to reuse the IAC housing so I cleaned the whole thing while it was out, as well as went through the steps to send carb cleaner through it while it was back on the vehicle and running. And that’s a good idea I’ll have to look into getting something like that
 
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mikemunz said:
I did both. I replaced the throttle body and had to reuse the IAC housing so I cleaned the whole thing while it was out, as well as went through the steps to send carb cleaner through it while it was back on the vehicle and running. And that’s a good idea I’ll have to look into getting something like that
Click to expand...
Since your IAC was clean, a good second guess would be the throttle position sensor is going bad. That's assuming your clockspring is good since a bad/electrically noisy clockspring can fool the PCM into thinking the TPS is going bad.
 
Jerry Bransford said:
Since your IAC was clean, a good second guess would be the throttle position sensor is going bad. That's assuming your clockspring is good since a bad/electrically noisy clockspring can fool the PCM into thinking the TPS is going bad.
Click to expand...

That was my next thought was the TPS. I’ve read some other posts talking about somewhat similar things but not exactly what I was experiencing. How about the whistle noise? Vacuum leak or no?
 
mikemunz said:
That was my next thought was the TPS. I’ve read some other posts talking about somewhat similar things but not exactly what I was experiencing. How about the whistle noise? Vacuum leak or no?
Click to expand...
Whistling could be a vacuum leak or maybe really it's a noisy idler pulley.
 
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