Yes the service manager was fired for unknown reasons.The dealership ended up going through GM protocol steps and eventually something to do with the front end was inspected and replaced(bushings).Has improved significantly,sad to say the vibe ration is rather minimal now.But still present.I just ordered new 18" aluminum wheels and will be having them mounted next week along with new tires.Hopefully this helps.Most likely purchasing Firestone destination A/T's.Have to be much better than the stock steel wheels and 17" Bridgestone duller tires.Crossing my fingers!