Hello and welcome.
Was wondering what the last part of your post means...
"on 17"
A vibration after a certain speed is usually caused by a tire / wheel assembly being out of balance, or a wheel is bent.
Poor tire condition can also make a vibration.
GM Dealer Technician
18 years plus at same GM dealer.
Try rotating the tires to seei f the vibration goes away or changes.
This would definetely show a bad tire or wheel.
Sometimes a bent wheel can take a little while to cause the steel belts inside the tire to shift, thus causing a viration.