o2 question
 

I have a check engine light for a bad o2 sensor. It says sensor 1 bank 2, which sensor is this?

Also I thought I seen that everything but bosch sensors go bad fast? Is this true?

Bank 2 is downstream. And if ones bad, the others right behind. Don't skimp on quality, either. I spent over 100/ea. on mine... I was recently informed I paid too much by another CF user, but they are warrantied and made of quality materials. So I figure I'd payed as much as I needed to get the right part.

Cool thanks. Ill go bosch then which are 70 a piece. I assumed it was downstream.

Wow now! Be wary of Bosch. I've heard Bosch o2's aren't the best for jeep. Idk, just go oem.

O ok. I thought I read somewhere they were the best, maybe I read wrong. Ill do more research. But I need to get somthing soon, I'm not a fan of 8mpg, and rough idle. Not sure if its the o2s fault but I'm sure it dosnt help

I'd be willin to bet it's the o2s.. All the symptoms are there. I would agree that Bosch is generally a reputable company, but I know I've heard debate on things like the Bosch spark plugs for jeep.. Might not be for o2's though.. Do a thread search and if that's a bust, start a new thread about it... Idk...

Did some quick research and am reading exactly what you said. Thanks for the help. I think I'm gonna go with ntk/ngk , which is who makes the oem.

I just replaced my 1st upstream sensor with a bosch. Used them on my Chevy blazer and never had problems with them.

This is wrong. If you have a v8, it will be the bank that has cyl 5678, upstream sensor. If it was the down stream o2 it would say sensor 2, bank 2. Up stream o2 are what monitor the air fuel ratio of the jeep, I would replace both, the down stream ones are behind the cat, and just read if the cat is working.

If you plan on keeping the vehicle, I usually recommend replacing both of the sensors. They have a finite lifespan of between 100k and 150k, depending on the efficiency of the engine.

My first choice for oxygen sensors is NTK, the oem supplier of oxygen sensors to Jeep. I personally haven't had any trouble with Bosch, but the resistance values in their heater circuit are a little different than the NTK.

I agree with this. The 4.0 Jeep really doesn't have a bank 2. I also think that if it was the downstream O2, there would be a code for a bad cat.

The upstream O2 is the one that sends info to the PCM for setting fuel trim. The downstream O2 monitors cat efficiency.

I'm gonna replace both with ntk then.