I searched through the forums, and found some clues, but here's the deal, and I apologize if this has been posted several times.

98 XJ, bought it 2 mos ago with 190k miles on it, runs great, did a full tuneup and was getting about 18mpg.

Recently, in the past couple weeks, its gone down to like 11 or 12 at the most.

I do have a small exhaust leak, which i'm going to fix, and also need new rear shocks, but I'm wondering if there are any other troubleshooting things i can check.

ALSO, sometimes i hear a "gurgling" sound coming from my gas tank area after I park and turn the engine off. Best I can come up with to describe it.

Thanks!

 

There actually is another thread just like this going on right now here. You should at least get an idea of where to start from that thread