the vibration at idle could be your harmonic balancer, crank pully look at it when your idleing if you have a wobble that should be the vibration also check your flywheel for cracks, the guys are right about the heads cracking ,head casting 0331 is quite prone to it between cylinders 3 and 4 close too looking straight down your oil filler in the vaulve cover, just keep an eye on your coolant level mine kept dissappering from my overflow bottle good luck

 

You mentioned the catalytic converter shield as a source of the "vibration." The shield would produce an audible RATTLE because of vibration in the exhaust system. When you say "vibration", I assume that you mean that the vehicle actually shakes. Is that correct?

 

Sorry--I mis-spoke....rattle sound is more like it. NO--the vehicle does not shake.

Thanks,

Dan

 

Then the catalytic converter heat shield is the most likely source of the rattle.

 

Thanks for the feedback! I will definitely check that out this weekend and post result.

Thanks!

Dan

 

Looks like it's the transfer case shifter that rattles a bit at a stop. Any way to tighten that up easy? If I pull it up a little, it stops for a while....

 

My 1999 does the same thing, the lever rattles some, at idol....