Idle issue vehicle idles at between 1,500 and 3,000 RPMs?

ROSSMILLER

MEMBER
2002 JEEP WRANGLER TJ
2.5L
4 CYL
4WD
MANUAL
244,000 MILES

I have put a new IAC in, and it made a small difference but now we are back to the same issue. I found a vacuum line that was cracked and fixed that and no change in the issue. I’m thinking it could be the header and downpipe not getting a good seal at the flange. Vehicle when downshifting RPMs skyrocket. Even in first gear the vehicle will run at 2,000 RPMs and be pulling the vehicle along as if I was giving it gas.

Wednesday, December 4th, 2024 AT 6:37 AM

3 Replies

KEN L

MASTER CERTIFIED MECHANIC
54,137 POSTS

Can we run the codes to see if any are stored?

This guide can help:

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

And this guide will help as well, please go over it:

https://www.2carpros.com/articles/engine-idles-too-high

Please go over this guide and get back to us.

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Wednesday, December 4th, 2024 AT 11:36 AM

ROSSMILLER

MEMBER
2 POSTS

So, I have the code P1294 and P0320. 1294 is for idle malfunction. So, I changed the IAC. P0320 is for o2 sensor but they have been changed to and there is no difference.

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Wednesday, December 4th, 2024 AT 12:05 PM

KEN L

MASTER CERTIFIED MECHANIC
54,137 POSTS

If the PCM is getting an erratic signal it can cause this issue as well. The P0320 code tells us this.

Code P1294: Target Idle Not Reached

Code P0320: Ignition/Distributor Engine Speed Input Circuit Malfunction

Let's try replacing the ignition distributor and clear the codes to see what happens. Check out the images (below). Let us know how it goes.

Images (Click to make bigger)