It comes from a combination of wear. Wear on the camshaft, lifters, pushrods and then the valve stem. Add it all up and you get some tapping and at 127K not bad unless it is really loud.
How do you get rid of it? Replace some parts and have the head gone through at the machine shop. Replace the push rods and rocker arms. Run a little thicker oil. These old engines have big tolerances and can run straight 30W oil no problem.
Or turn up the stereo and don't worry about it until it quits.
89 2.5 TBI, 4" RC lift, 1" Booms, SYE, Adams Driveshafts front and rear, Ford 8.8 with 4:88s, BFG 33X12.50X15, and a ton of other stuff.
AF Jeep Club Tail Number 184