Going 50+ mph my passenger seat shakes like crazy mostly the headrest shaking is the normal? Lol

 

haha, your passenger seat is resonating with something, thats kinda awesome, a vibrating seat for your wife and girlfriend

 

Mine doesn't shake or vibrate on my V6.

As a matte of fact I just made a short video with my camera strapped to the passenger seat headrest and it was nice and steady.

 

Check the tires and drive shaft for balance issues.

 

Out of balance tires will do it.

 

I agree especially tires.

 

it's probably just possessed

 

Good thing I'm ordering new tires/wheels today ope that fixes it lol

 

LOL - totally struck me when I read this, +1

 

Mine shakes just cruising at 30mph.

 

Yup, first thing that came to mind is the wife loosened the seat bolts.

 

Wait you have a wife and girlfriend??

 

Of course he does he has a vibrating seat..

 

If the tires were out of balance, wouldn't he feel it in the steering wheel as well as the drivers seat too?

 

sounds like a typical V8 mustang problem..me no care!

 

That would be if the fronts were bad, if just the backs were off then I can see the seat doing what it is. In the 2003 Mustang Vert I bought some deep dish black bullets that at 1st did the same. I had to take it down 3 times to have the tire place put extra weights on it to get it to stop. It was a slight imperfection in the manufacturing but at 70 MPH it did what he is stating his car is shaking the seat.

 

Is your passenger window open? If I go on the highway I've noticed the same thing. But I attributed it to the wind shaking the headrest.