I have this vibration on my car recently also. Started suddenly. I have aftermarket wheels but they were fine for a while. Sudden start to the vibration just a few days ago. Had the wheels rebalanced. Did nothing. I'm about to trade this POS in on a 5.0 and never look back. I've always been a Chevy guy but we are getting crapped on and getting no support from GM or the dealerships that are supposed to do the work.
2011 2SS Black/Black
GMPP heads, GPI SS3 VVT, SP 1 7/8" LTs/cats, GPI intake, Vararam CAI, UDP, Yank SS 3600, DriveShaft Shop DS, ADM Cooler, 3.45s
GPI Intake and Cam for sale. PM me if you want either. Going to LS9 and LSA.