Lately my jeep has been running a little rough, like it's loading up on fuel. I just got back from a 240 mile trip and averaged 19mpg, but this last tank was sitting around 13mpg, and my current tank is looking the same. I've got the pacesetter header so it does leak at the Y-pipe, but I haven't noticed any other leaks before the O2 sensor. Is there anything else I should check? Would an exhaust sealer even be worth getting and putting around the Y-pipe? TIA

 

When was the last time you gave her a tune up?

 

do like the other post said and make sure of the tune up, also check the o2 sensor. I know it sounds odd if you have done it recently but i also have an 89 that i chased this problem forever. I was getting about 10 mpg! I replaced the sensor numerous times (under warranty) till i figured out the it was the heater element getting damaged and not working. Re-tapped the hole and replaced the sensor again and everything is working correctly again! Just a heads up on somewhere to look

 

A tune up is definitely due. Another thing is the engine stumbles a bit when the brakes are applied in gear (AW4) Kinda sounds like hitting the brakes without pushing the clutch in on a stick. It started when I hard wired the TCU into power mode.