It is normal for the steering gears to wear as your Jeep ages. Oversize tires, and serious off-roading can accelerate this process, and sloppy steering will be the result. There are two adjustments that can be performed to the steering box, Bearing preload, and gear back-lash. The proper procedure for performing the preload adjustment is a bit involved and requires some disassembly of the steering. However the gear back-lash is easily adjusted with a combination box/open-end wrench and a screwdriver, and only takes a few minutes.First jack up the front of the vehicle so the wheels clear the ground. With the key turned so that the steering is not locked and the engine is not running, center the steering then turn the steering wheel back and forth past the center position (¼ turn in each direction is sufficient), and feel for a very slight drag as it passes the center. If there is none, then the back-lash needs to be adjusted.
Locate the lock nut and adjusting screw on the top of the steering box (on 4.0 models it may be necessary to remove the electric auxiliary cooling fan to access this adjustment, and on the 2.8 you need to loosen the bracket and pull the charcoal cannister out to get to the gearbox). Loosen the lock nut and gradually turn the screw in (clockwise), until slight resistance is felt as the steering wheel passes the center position (this is easier with two people). Then back the screw out until the resistance is barely detectable. Now tighten the lock nut while holding the adjusting screw in place with a screwdriver. Re-check the steering wheel for resistance as it passes the center position. It should be barely detectable, you may need to re-adjust it if necessary.