"New" XJ issue

Wondering if I can get a few people's 2 cents here.

Driving back home from waterfowling, on the freeway, check engine light comes on. Earlier this morning before light comes on I notice I am getting very poor gas mileage. There are a few random idle spikes (300-350 rpm) while in gear on freeway. But the spikes don't propel the Jeep forward too much faster.

Hit the gas to see if there's a cut out, nope. But the rpm's come up against a disproportional amount of acceleration. Idle is good as can be. Thorough visual inspection checked out. Thinking this is O2 but wondering if maybe a position sensor with the spikes. Oh, and I am only at 49k miles, first gear no problems, just at freeway speed.

Thanks.

It's a 2000 btw. Thanks again.

Start by pulling the code(s) that were thrown. This will give you a very good indication of where to start. Autozone will read the codes for free for you.

As for the crappy mileage, i'm not sure. But you mentioned small spikes in engine speed while on the highway, followed by the check engine light. I have to wonder if it's TPS related (atleast on the engine spike part)

Thanks Tim. I'm sure I will be throwing even more money autozone's way tomorrow after the scan.