loligator

Hi guys,

I recently picked up a 96 Cherokee. It was sitting for about a year if not slightly longer and is in need of a tune up. As I was driving her home from the PO's house the check engine light came on. I forget the code but it was the O2 sensor code. I've heard an engine in desperate need of a tune up could start throwing codes related to emissions stuff although I don't know how true that is. I know a lot of backyard/DIY mechanics who aren't the sharpest tools in the shed so who knows if that's actually true . Anyway, after doing the plugs and wires (still need to do cap and rotor; waiting for them to come in the mail), I reset the CEL and have driven her a few times since mostly around town. Enough to go through two tanks of fuel. My fuel mileage is absolutely terrible. I get about 140 miles to a tank. My 95 gets 200-220 depending on driving conditions so something definitely isn't right. I can't imagine finishing the tune up will yield me a 60 mile per tank improvement so something else must be up.

When I purchased my 95 forever ago it had a bad O2 sensor and the PO was honest about it and inform me prior to purchasing. I drove it around for a bit prior to changing it out and it still got about 170-180 miles out of a tank. Granted 95 is OBD I and only has one O2 sensor where 96 is OBD II with two O2 sensors so I imagine the experience could be different.

If I do in fact have a bad (or two bad) O2 sensors on the 96 would I see such a dramatic decrease in MPG?

puredrive

yep..that's for all cars that have bad 02 sensors. Might as well replace them- I got mine from Amazon.

loligator

i could only find generic o2 sensors. did you get one specifically for a xj? i also couldn't find one specifically for the front or back. are both the same since it has 2?