Rough idle + slight misfire - Page 2 - Jeep Wrangler Forum
Jeep Wrangler Forum

Go Back   Jeep Wrangler Forum > TJ Jeep Wrangler Forum > TJ Tech Forum

Join Wrangler Forum Today

Thread Tools

Please support our sponsors and let them know you heard about them on
Old 09-12-2013, 12:43 PM   #31
rkulp89's Avatar
Join Date: Aug 2013
Posts: 57
Originally Posted by Reznor View Post
Here's the thing about the O2 sensors, and why I ruled them out in my own situation:

Firstly, there is no CEL. This doesn't necessarily mean they are not at least somewhat faulty, but is a good start.

But when a vehicle is first started, it runs in open loop - completely bypassing the O2 sensors until it warms up and then goes into closed loop. So if the idle/running occurs when the vehicle is dead cold, then it shouldn't be the O2 sensors.
I didn't know about the open/closed loop. Does that apply to all vehicles or just jeeps?

rkulp89 is offline   Quote
Old 09-12-2013, 10:38 PM   #32
chevymad's Avatar
Join Date: Jul 2012
Location: Skamokawa, WA
Posts: 413
All vehicles, though there is some learning done that the ecm applies to the next start.

My jeep ran the same way before and after all 4 new o2 sensors. NTK brand. One cleaning was before changing the sensors and one was after. As said, it runs smooth and quiet after cleaning for about a month.. a little less actually the 2nd time. Runs fine on the road and no check engine light. What I really found interesting was the effect of the pure fuel vs E10.

chevymad is offline   Quote
Old 09-14-2013, 10:44 AM   #33
Shane20's Avatar
Join Date: Aug 2013
Posts: 52
Originally Posted by Jerry Bransford View Post
I'd bet more on one or both of your upstream 02 sensors being bad, I really doubt your fuel injectors have anything to do with your rough idle.
Thats where I first started. I had a cel light come on showing the bank 2 sensor 1 was bad, so I changed it out but i figured since they were pretty cheap I would replace all of them. since I did that I have had no cel light come on.
Shane20 is offline   Quote
Old 09-17-2013, 01:34 AM   #34
Shane20's Avatar
Join Date: Aug 2013
Posts: 52

Shane20 is offline   Quote

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Download our Mobile App

» Network Links
»Jeep Parts
» Featured Product

All times are GMT -5. The time now is 08:11 PM.

Jeep®, Wrangler, Liberty, Wagoneer, Cherokee, and Grand Cherokee are copyrighted and trademarked to Chrysler Motors LLC. is not in any way associated with the Chrysler Motors LLC