where's the vibration comming from in my rear interior?

[b3nsonx]

Sometimes when i drive, there will be a vibrating sound in the back seat area of my car.
Sounds like plastic that's loose, but im not sure where, because im driving.
i know it's my exhaust that's causing it to vibrate, but i dont know exactly where it's vibrating at.

anyone else have a similar problem?

[hs06]

yeye my brother had same problem its lose panel a clip of some sort