RICZR2

When I first start my XJ up, it rattles like crazy. After driving a few miles, the rattle will stop. I'm told by a few people that a lifter isn't pumping up. If I change the lifters do I need to change the rods and if I change the lifter and rods do I need to change the cam shaft. I have 114,000 miles on my 4.0.

peep

You can use new lifters on an old cam.
Don't use old lifters on a new cam, don't reuse lifters IF you mix them up, they are broken in to a specific cam lobe.
Try an oil additive like STP or Wynns targetted at freeing a sticky lifter, change your oil regularly.
I've got 481000+ km on original Renex 4.0, yes it makes noise, I drive a lot and change oil every 50000-7000km (monthly), yes it makes noise, yes it runs nice and I use one liter of oil in between changes. New filter every change, I believe 500 is within reach, then goin for 6000000. Try the Wynns, a lifter change is an involved proceedure. Good luck.