Very cranky starting when hot

Have searched 35 pages and in need of help as where to start looking to cure prob.......
92 XJ 4 litre 170k starts fine cold-runs fine. After a long hard trip it takes 20 to 30 seconds to relite, if engine it warm or hot, and stumbles until cleared up. Will run fine after cleared up. Have smelled raw gas around engine, but do not see any signs of gas. Gas milage seems to be worse. Engine temp is good all of the time. Have not really started to spend time trying to cure prob...looking for areas of where to start?????? Any one have ideas of where to start??
Thanks

170 miles

ive had three cherokees and all of them had fuel pump problems around 150-175000 miles. next time it acts up turn the key on and listen for a whirring sound from the rear.if none check your power and grounds from the battery, no go? pump is probably over heating a sign of failure. i recommend ome parts napa and auto zone seem to fail quickly, warrantied but too much work for a once a year replacement.

mine is doing the same thing.... I've had some guys say it might be the IAC.. Don't know yet.. Any progress?

Poor gas mileage might be the O2 sensor, put it does not affect hard starting at all.

Hard one to figure, but might be a sticking IAC. Might try just cleaning and oiling the threads on it. I say sticking IAC as it might be OK for a cold setting, but may be sticking trying to reach a hot/warm setting for starting. Also clean the throttle body areas where it seats.