rear o2 sensor

[thenry]

have a 1997 jeep cherokee previous owner removed cat and downstream o2 sensor ;issue is that it has an intermittent rough idle gives a code for rear o2 shorted and that is all.wondering if the rear o2 is needed for fuel mixture or not my mechanic says no but some posts conflict this. is there a definite answer out there?

[LizardRunner]

with out re-programing your ECU you're going to need that O2 sensor.

[uberxj92]

you need both 02 sensors on those jeep so equipped. they make after market wiring that will trick your ecm into believing that the sensor is still there. if you install a sensor after removing the cat you will give bad info to your ecm & have issues there. i have learned the hard way that 97-01 xj's are very year & model specific so messing too much with the jeep will teach you the hard way.

[4.3LXJ]

The front O2 sensor is the one that determines mixture. The rear O2 sensor monitors the cat. But if you are having a rough idle, a question I might ask is how long has it been since the front one has been changed?

[Gonepostal]

you need both 02 sensors on those jeep so equipped. they make after market wiring that will trick your ecm into believing that the sensor is still there. if you install a sensor after removing the cat you will give bad info to your ecm & have issues there. i have learned the hard way that 97-01 xj's are very year & model specific so messing too much with the jeep will teach you the hard way.

Where would find the wiring to trick mine. I lost one on the trail and this would have been handy when I limped back to town.

[uberxj92]

i saw it a while back on line. i am trying to search for it again to see if i can find it for ya. try searching google.