I just bought an 01 GP GT coupe with 142k, I noticed that above 30-35 mph it vibrates a bit, I can feel it in the floor and seat but not in the steering wheel. Doesn't go away when I put it in neutral while cruising, I'm about to jack the car up and check for play in the wheels, and next week I'm going to have the tires balanced since I know the dealer put new tires on recently, any other suggestions if these are not it? Or what it most likely is if there is play in the wheels? Also, I noticed a slight hesitation when cruising at about 30-35 in third gear, seems to be chugging a bit. Is this a transmission issue, or maybe bad plugs? And finally, just a couple days ago the blower got stuck on defrost, the knob turns but doesn't change anything, probably a vacuum issue or electrical?
