The ignition coil has been replaced several times. After several break-downs, I finally found out that Chrysler Corp. had designed a 2nd generation coil for this model year. I'm not sure if this is true for the 4.0L. Replaced the aftermarket coils, that had failed repeatedly, with the factory 2nd gen. coil at approx. 76,000 miles. and haven't had a problem since.
Several problems with the A/C. Mainly, loss of refrigerant due to leaking O-rings. Although I try to maintain the system by frequently running the A/C during the winter months (lubricating the O-rings), I have had to replace O-rings and recharge the system every summer. In 2002, a mechanic recommended replacing the condenser coil also. A very labor intensive task.
I've also had a couple of cooling system problems. Replaced two water pumps and one radiator. The vehicle seems to run excessively hot (especially when towing my boat). 200 - 215 degrees normally and 235 + when towing. The local Jeep dealer's mechanic said that this was normal. H'm?
Replaced brakes and rotors at 50,000 miles., 70,000 miles., and again at 90,000 miles. I contribute the warping rotors to towing in the mountains. Although I do not tow anything that exceeds the Gross Weight Rating for the vehicle, the rotors continue to warp excessively. Hopefully, a new brake system design is being implemented on the newer models.
The computer system in the vehicle has had a few glitches. Sometimes it does not allow the engine to idle and other times it has simply shut the engine down during operation. Simply disconnecting the positive battery cable for 20 minutes (allowing the computer to reset) usually solves the problem.
Other minor replacement items include:
EGR valve at 80,000 miles.
Rear lift-gate shocks at 65,000 miles.
CV joints at 40,000 miles.
Front stabilizer shock at 65,000 miles.
Transmission oil/filter change at 90,000 miles.