Hey guys, I've been noticing that when I'm driving sometimes when I'm going at a steady speed I see from the corner of my eye my passenger seat seems to do a lil shaking, not like the seat is coming off the car but it does shake.

What could this be?? And what should I check??

The first thing comes to my mind is a loose bolt or nut.

Yeah check the bolts holding down the seat, it is possible one or more have came loose. It'* not common but it can happen.

Rear tire imbalance?

Check the seat it won't hurt. But that vibration you are seeing in the seat could be something to do with the suspension. When was the last time you had your tires balanced and rotated ?

Also it wouldnt hurt to check the ball joints and tie rod ends.

Well I just got a new tire probably in June and they checked everything (at least they said) But I'll have to check the stuff out..

It started during the winter after I hit a snow pile, but then I didn't notice thats why I thought it was nothing, but then it started back up and does it

Well you might have knocked a weight out a little bit . Or you might have bent a tie rod like I mentioned.