Yesterday i was driving my teg on the freeway and the car started to shake at highway speeds of 65+mph. The faster i went, the more vibration i get. The whole car shakes. When i drive it around town it's fine. any ideas?

 

Tire pressure or alignment needed.. Or wheel balance.

 

really bad alignment? my steering wheel shook really bad at 70+ miles but got it aligned and fixed it. Not sure tho?

 

I don't think it's the alingment because the car goes fine when i let go of the wheel. Oh yeah, i also put that crap fix-a-flat in my tire yesterday because it was always getting flat. could that be a possiblity of throwing the tire off balance?