I am curious on how much a faulty o2 sensor on jeeps play a role on performance. Could it make your engine skip? I have changed spark plugs, spark plug wires, distribute cap. The engine still sputters. I know my exhaust manifold has a crack but I'm curious if the o2 sensor could be the issue. The code when I pull it only says o2 upstream. I am aware that NGK / NTK replacement O2 sensor should be what I order if needed. Thanks for any help y'all can give.
How much does a faulty O2 sensor affect performance?
- Thread starter RAC02
- Start date
Yes, the upstream O2 sensor dramatically affects engine performance. A bad one will make your engine run like crap.
Replace it with an NTK sensor.
See this thread if you need the correct one:
https://wranglertjforum.com/threads/the-official-jeep-wrangler-tj-oxygen-o2-sensor-thread.4068/
Excellent, correct me if I'm wrong, but the 4cylinder 2.5L has just bank 1 sensor 1 and 2. There is not bank 2? And sensor 1= upstream 2= downstream. Could a vacuum leak be the real problem, or not?
Last edited:
Ok read the article. I did hear that a bad vacuum leak could mimic a bad o2 sensor. It sounds like I have a vacuum leak and I know I have a cracked exhaust manifold. Could either one of those throw a faulty o2 sensor code?
I have heard of exhaust leaks upstream of the sensor drawing air in on the low end of the exhaust pressure pulse, which screws with the oxygen concentration picked up by the sensor.
Generally, if I'm trying to diagnose a problem, I try to have all of the known issues addressed so I know I'm not chasing my tail and spending money on parts that may not need replaced. Right now you have a cracked manifold and sounds like maybe a vacuum leak, so I would take care of those first before replacing a sensor that has not given you any other reason to believe faulty.
Generally, if I'm trying to diagnose a problem, I try to have all of the known issues addressed so I know I'm not chasing my tail and spending money on parts that may not need replaced. Right now you have a cracked manifold and sounds like maybe a vacuum leak, so I would take care of those first before replacing a sensor that has not given you any other reason to believe faulty.
Steve Rodgers
TJ Enthusiast
This is great advice!!!! I know your right. The code does say o2 sensor and my jeep is a 2000 and a doubt it has ever been changed so I may change it as this part I found for 23 dollars. But I agree with what you said.
I do wonder though if the cracked manifold would generate a downstream error, or upstream? Because this is a upstream error.
Somehow I completely missed that you have an O2 code. Depending on what specific code it is, it still may not be bad.
If the crack is upstream of the sensor, it can affect that sensor. The downstream sensor just looks at how much less oxygen is in the exhaust than the upstream sensor to determine the health of your catalyst. An exhaust leak between the sensors can therefore trigger a catalyst efficiency code.
Similar threads
