O2 sensor, if you have replaced it already, pull it out and make sure it hasn't burned it again. Jeeps can be notorious with these O2 sensors.
There are several things that can cause your Jeep to stall while idling. The timing may be off or your fuel filter may be clogged.
If the car dies while idling, the timing might be off. Other causes can include a clogged fuel filter or a bad spark plug.
something is loose
Check engine light on, low tire pressure, aggressive driving, excessive idling, dirty air filter, brakes dragging,
my experiencess with vehicles that cut out while idleing would be a fuel filter or fuel pump problem.
check for clogged fuel filter,or bad fuel pump
Taking your foot off the accelerator.
a dirty air filter or a dirty fuel filter will cause a diesel to smoke
old fuel filter
It is idling. This is hard for an engine to do smoothly.
Probably wheel bearings or wheels are unbalanced
Sans other problems, my experience dictates that you have a fuel filter that needs changing. Idling? hardly any pressure through the gas lines. Accelerating? pressure builds and, the fuel filter being clogged somewhat, the gas can't get through, and it's choking, so to speak. Try changing the filter. Get a Chilton's mechanic repair book and look at the trouble-shooting chapter, and look for your problem.