Issue with suspension maybe?
 

Hi all,

Looking for some advice. Recently I heard some clunking coming from the rear of the car when going up and down the ramps in my parking garage. It went away after a few weeks but now when I am driving the rear end is almost like floating around bouncing from left to the right to the point I have to slow down to straighten the car back out. It's not drivable at speeds over 70+ now because of the bouncing back and forth.

Any ideas what it could be? I have an appointment with ford later today. Just getting anxious to figure this out.

2015 GT PP, no mods besides exhaust which has been on since day 1.