Have you replaced the fuel filter? Cap and Rotor? Plugs?
Does it throw a check engine code?

For those weird intermittent problems I always start a tune up if I know the engine has been sorta neglected. It usually doesn't fix the problem but you get two things out of it.
1. You just did the routine maintenance that should have been done.
2. You can inspect the other systems while in there.

It sounds like it could be a failing distributor bearing, plugged filter, ETC... Internet diagnostics is fun and useful <img src="/forums/images/graemlins/cheers.gif" alt="" />
If you have done a tune up recently, Check out the distributor shaft. If the bushing is failing, the extra clearance allows the magnetic pickup to change clearance giving it weird mis-fire characteristics when warm.
If the distributor feels tight, I bet it is some weird intermittent electrical problem in a weird unrelated system to all the ones most people say (isn't that helpful!).
Also... It could be a faulty TPS...
Or...
....
...
If youÆve tried everything... you could try an O2 sensor, but I doubt it would fix it. When you floor it, the jeep goes open loop and ignores the O2 sensor.