I had replaced my thermostat probably 2 months ago after some overheating issues. It has been fine and then all of a sudden it started overheating again at highway speeds. It was fine when driving at slow city speeds. I have purged all of the air out of the system while the jeep was inclined. Did that 2 nights in a row until I got no more air out. Water pump is working, thermostat is opening when it should. Fan is kicking on, system has the proper coolant, and the radiator cap is OEM and correct for the Jeep. Has anyone ever had a bad coolant temperature sensor? I was wondering if this could be my problem since all of the other common issues seem to be ok. Thanks in advance.