Jeep Repair: 98 Grand Cherokee 5.9 limited with valve leak?, valve lifter, vacuum leak

Question
Hi Kevin.  Thank you for your service to all of us site users!  My Jeep has had this issue for several years where by acceleration causes a 'chain rattling' sound or air/vacuum leak from engine compartment.  Dealer has never isolated this issue but a friend into cars said it may be valve/lifter related.  It has become more pronounced over time but doesn't seem to be hurting the car's performance too much.  I'm embarrased at this point becasue it sounds like a clunker when I drive especially accelerating quickly.  Oh, octane booster seems to make for a short term reduction in the intensity of the noise.  I alsways use premium gas.  Any ideas?

Answer
U have spark knock.   Sounds like a bunch of coins ratting around in a tin can right?? U have carbon build up on your valves. Mopar has some stuff u spray down into the intake and let sit for 30 min then drive the piss out of it after that  and smoke the neighborhood out hehe.
Its called combustion chamber cleaner from Chrysler  a dealer will have it.