Hi, don't know much about your type of jeep, but my zj was doing same thing. I too, tried replacing things; fan clutch, thermostat, rad, rad cap, water pump, and nothing seemed to work. Turned out I had gotten a dud thermostat right out of box, replaced it and no problem now. You might also check whether your rad fan is working right, at speed, the airflow through rad will keep things cool, but when you stop there is no forced airflow and things will heat up. Don't know if this will help or not, but good luck.