I have the same problem!!!!!!! I was just informed today by my mechanic friend, that it needs a computer.
It has been doing this for over a year, but we could never get it to do it frequently enough to diagnose. Finally it has gotten worse, and He notified a friend at Jeep with his diagnostics, and was told the engine computer is bad. (dealership part only). I guess I will call Jeep to see how much they are going to rip me off for this part! I'll keep you informed.
2000 Jeep Wrangler Sahara, 4.0, Auto trans., Forest Green. 33x12.50x15, 2"BB, 1"BL.
Christian Jeep Club Member #65