The Official Jeep Wrangler TJ Oxygen (O2) Sensor Thread

I have a 2.5 01 tj that keeps idling rough when hot. So far I’ve changed all my spark plugs including wires. Rotor cap, iac valve. And the upstream 02 sensor. Not getting any check engine light. Drives fine just idles rough when warm and almost stalls when put into reverse. Any suggestions?
 
Mcrod126 said:
I have a 2.5 01 tj that keeps idling rough when hot. So far I’ve changed all my spark plugs including wires. Rotor cap, iac valve. And the upstream 02 sensor. Not getting any check engine light. Drives fine just idles rough when warm and almost stalls when put into reverse. Any suggestions?
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Have you run a compression test on it yet? If not I would start there
 
I have a 2001 Jeep Wrangler TJ that’s reading a P1195 code. It says Catalyst Monitor O2 Sensor 1/1 Slow Response. Do I just need to replace the Bank 1 Sensor 1 O2 sensor to get this code to go away?
 
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hannahers18 said:
I have a 2001 Jeep Wrangler TJ that’s reading a P1195 code. It says Catalyst Monitor O2 Sensor 1/1 Slow Response. Do I just need to replace the Bank 1 Sensor 1 O2 sensor to get this code to go away?
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Generally it's best to replace them all at the same time. But that's not a hard fast rule. How long has your CEL (check engine light) been on?
 
reddvltj said:
Generally it's best to replace them all at the same time. But that's not a hard fast rule. How long has your CEL (check engine light) been on?
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Okay, I just actually went and looked at my Jeep to see if I could find them and I was able to locate all four. So I’m going to replace them all. It’s been on for about a week, but I don’t drive it all the time. It came on about a week ago and I haven’t driven it since then.
 
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hannahers18 said:
Okay, I just actually went and looked at my Jeep to see if I could find them and I was able to locate all four. So I’m going to replace them all. It’s been on for about a week, but I don’t drive it all the time. It came on about a week ago and I haven’t driven it since then.
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Have you tried clearing the code to see if it comes back yet? If not I suggest you have the codes cleared and see if it comes back.

Sometimes the computer has a hiccup.
 
reddvltj said:
Yes you could drill new holes and weld in new bungs for the sensors. Have you tried using a box end wrench and a cheater bar to get the lowers broke loose?
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I finally got them! Put a tire splitter against the end of the O2 socket and hit it with a mini sledge a few times... basically made an impact hammer. Last ditch effort but I got them. 10 minute job took me 4 days lol but got it done and replaced correctly with no drilling.
 
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Wish I found this website first.
1997 TJ 2.5L manual transmission.

I replaced my exhaust system and reused the O2 sensors. Buggered them up a bit removing.
After a month, I was getting rough running when Jeep changed from OPEN loop to CLOSED loop.
(Monitored with scanner.)

Replaced the front O2 with an Ultra Power brand.
Still, rough running when Jeep changed from OPEN loop to CLOSED loop.
Two minutes to clear up and run normal.
Finally threw a high sensor voltage code.

Bought a NTK, now all is right with the world.
 
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dennis461 said:
Wish I found this website first.
1997 TJ 2.5L manual transmission.

I replaced my exhaust system and reused the O2 sensors. Buggered them up a bit removing.
After a month, I was getting rough running when Jeep changed from OPEN loop to CLOSED loop.
(Monitored with scanner.)

Replaced the front O2 with an Ultra Power brand.
Still, rough running when Jeep changed from OPEN loop to CLOSED loop.
Two minutes to clear up and run normal.
Finally threw a high sensor voltage code.

Bought a NTK, now all is right with the world.
Click to expand...
This forum will save you a lot of money so you can spend it on more mods. 🤣
 
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I’ve received a P0133 code on a ‘97 with the 4.0L so I searched to see what it was and how to fix it. I found it could be the sensor or maybe a cat going bad. I also read that it could be a dirty air filter. The air filter was pretty dirty so I took care of that. Put a clean air filter on it and reset the code. A week later I got the code again. Before I bought two new sensors I would check the cat to see if it had physical signs of problems. The problem I saw was that it has no cat. I can see the PO replaced the muffler and put in some pipe to fill the gap where the cat was at. Now I’m wondering if it still is the sensor or the missing cat causing the code. Once the code was once cleared again I ran a test in the system and I think it looks ok. What do you think?

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