My sister has a 96 Cherokee. It has nearly 300,000 miles on it and is still
going strong.
Repairs have been few and far between, and none serious, I think the worst
was a bad crank sensor around 200K.

randy1128@webtv.net proclaimed:

  The engine can easily go 200-300K miles with halfway decent care.  For
  some reason I've seen Cherokee owners complaining of worse gas mileage
  than the same drivetrain in the Grand Cherokee.  In the Grand, that
  engine should get 20-21 mpg highway...dunno if aero or just driving
  style.  The low end torque makes it much quicker in traffic than the
  horsepower would suggest.

  Make sure the 4x4 stuff is all functional of course.  Some common
  problems with the 4.0:

  o  Exhaust manifold likes to crack.  Replace with aftermarket or
     newer factory--which costs more than a first class aftermarket.

  o  Crankshaft position sensor, more often just dirty connector than
     actually being bad.

  o  Some of the factory catalysts are crap...any rattle, replace it.

  o  The valve cover gasket will leak and look like a rear main seal or
     other engine leak.  If the side of the block is wet, it is the
     valve cover gasket.  Some of the aluminum aftermarket ones leak
     worse than factory.

  o  The serpentine belt should be changed roughly every 60K miles, but
     it won't break anything if it goes out.

  Check for any sign of overheating.  The 4.0 has a very robust cooling
  system if taken care of... never managed to get up to 210 on the guage
  even crawling in Vegas summer traffic with the A/C on full.

  If you buy a used one, probably a good idea to flush all fluids, being
  sure to add any friction modifiers called for.