Where is the O2 sensor located on my 90? I think I read that there is only one.

 

One in the downpipe and one right after the cat (at least i'd think there's 2). Get down there and take a peak

 

There's only one on my 87. Between the down pipe and the cat

 

Okay thanks, what exactly do they look like?

 

Only thing with wires coming out of it on the exhaust. It's just after all the pipes come into one

 

look for something like this on your exhaust, close to the engine. look from the drivers side under the door...
btw, it is the thing with the wire on it.

 

this might help a little

 

One o2 sensor right on the down pipe after all the manifold tubes come into one. Follow the front axle towards the center and spot the exhaust pipe with the notch in it (looks like something flat hit it). That is the downpipe, follow that up until you see a spark plug type thing with wires running out of it. Best to test it with a meter (can't think of the name right now) to make sure it works or not before you spend $50 on a new one. Renix jeeps don't have an idiot light, so us owners fend for ourselves. Codes can't be read either, they don't get stored. And for an easier approach, just find the exhaust and follow it towards the engine until you find the sensor. There should only be one.

 

There ya go

 

To get to mine, (on my 90), recently, I jacked up the frame so the left front was hanging and went at it from the front. Since I was sure it was toast, I cut the wires off so the 7/8 box wrench would go on.

 

Thanks guys!!!