Hey
My wife had a 99 WJ limited with a 4.0L and it was ok but a little sluggish (IMO), we also had problems with the heater/cooling diverter doors, and the associated cooling fan ($1300 bill), also ran into a lifter type noise after running 10% ethanol for about 6 months. Also the drivers side mirror heat wouldnt shut off turning the mirroe gol in color.
I drove a 99 WJ with the 4.7L V8 which was a much better engine in power. Gas mileage was from 17 to about 19.4 depending on summer blend gas vs. winter blend. I also had the diverter door issue and intermittent climate control assy. also needed a new resistor to control the fan speed. That was about $800 bill. I had issues with brake rotors and at the price of 4 new discs, I decided just to true them up as good as possible and throw new pads on. I also ran into an issue when going through some mud in OK and screwed up the front drive shaft disks and was told I would need a new from driveshaft, dealer quoted me $2200 bucks but get an aftermarket one that replaces the clutch setup and install a new shaft. I did run an wilderness sport rack on top with a pair of Hella 500's and it made little difference in gas mileage but the noise was significantly more. The biggest complaint I had was a lack of cheap aftermarket support unlike regular Jeeps or Cherokee's and the fact that even with a good lift you can't put decent rubber on (like 33-35's). I wish they had put the 4.7L into the new JK, that would be an excellant combo imho. Watch the WJ's seat warmer, because if it's on high, it will cook your buns! LOL
Pete Wilson
P.S. We don't own either WJ anymore. Wife drives a Grand Caravan and I have a 4X4 Ford F150 Extended Cab. I want a JK but will have to wait for now.