I own a 2005 Kia sedona lx with roughly 105k miles on it. the van has been shaking at around 60mph and up. i went and got an alignment, a hub bearing, and the two front tires replaced, but the shaking is still there. it only appears when accelerating, and if i let off the gas and coast, it pretty much goes away. any ideas?
High speed specific vibration usually means worn tires or worn struts, tires out of balance, low tire pressure on one wheel, or of course front-end problems. If you’ve had the car aligned recently, the front-end should have checked out okay. I’d have the rear tires and (front-end) struts looked at. It might also be a motor mount as suggested, but I think you’d likely feel a vibration while stopped in drive as well. Not always. Something else to look at though.
If its acceleration only & goes away when coasting then I’d suspect one of the inner CV joints.
Another vote for a worn or binding CV shaft. Unfortunately the shop may have to remove it (them) to inspect.