I have a 99 and an o1 xj. From what I can tell the 99 has 2 o2 sensors and the 01 has 4. Can anyone verify and explain this. I would have thought the 2 vehicles would be the same. Thanks!

 

Yes that is right. My 00 had 4. I believe the exhaust manifolds are different and it uses one 02 sensor for 3 cylinders and another one for the other 3. I am sure it has to do with emissions crap and fuel economy. Or maybe jeep just wasn't selling enough 02 sensors using only 2. Decided to double the chances of a 02 sensor falling.