Originally Posted by Truitt
I don't really thing is an engine problem. It runs really smooth the whole time. No engine codes at all. I feel like its a drivetrain thing. But it doesn't make sense to me that I doesn't do it all the time or become worse at highway speed.
If it only happens when you "punch it", then one might be tempted to suggest that you *don't DO that*!
But, there is probably some hidden issue just waiting to bite you on the butt so, as Project1 suggested, check your motor and transmission mounts. Also look at the condition of your U-joints and bushings.
You say you just bought it WITH a 3" lift installed and no SYE, correct?
Can you tell if there is a T-case drop kit installed?
Chances are your drive line angles are off. MAYBE it's off just enough to only cause vibes under a heavy load
And to verify how much lift you have, measure from the center of the axle to the bottom of the fender flair. Stock is 17.5" front and 17" rear.