2014 5.3 3.42 20" Continentals 17,000 miles. My truck rode like butter, better than my sisters caddy till I got about 13,000 miles on it. Started vibrating at around 73mph (not all the time). Brought it in said I had 2 bad tires,had to pay 40% for 2 new tires, still vibrates. Been trying to figure out when it happens. I swear it seems better when I have a full tank of gas. Anyone else notice this?