Hello everyone. I did a search but really didn't find what i was looking for. I just purchased a used 2007 silverado with 22,000 miles. The truck has already been lowered and sitting on 22" rims. When i test drove the truck i noticed a slight shake or shimmy at free way speeds, 60 -70 mph. The dealer told me they would have the alignment and the wheel balance checked and i would pick it up on the next day, i still haven't taken it home yet. Next day arives and as i show up at the dealer my salesman comes to me and says something still isnt right with the truck. He had just test drove it and said there was a steering wheel shake under hard acceleration going up hill but not down hill. So i test drove it my self. Went up the hill under hard acceleration and felt a little shimmy in the steering wheel. I turned around and accelerated hard down the hill and suddenly the steering wheel shook it's head like a wet dog. Never got up to freeway speeds, just pulled it into the dealer ship and started looking it over. Noticed they replaced the right rear tire and put the wrong size on, its now a 305 instead of a 265 like the others. Is this causing the problem or is it something far worse and maybe somethign with the lowering work that was done previousely? Needless to say they said they will make it right or i don't have to buy the truck but i really like it and want it, need it. Please advise!