[ninian]

I still havent figured my noise out. It appears to be coming from the back of the car, but I have tried lowering/raising the headrests and I have made sure those clips for baby seats are properly closed. It sounds like a vibrating plasticy kind of rattle but for the life of me cant figure it out.

 

[ninian]

Get someone to sit in the back and try and locate the noise while you are driving. Or have someone else drive (I know its an absurd notion to have someone else drive) while you locate the noise in the back seat.

I was driving with a few people and had them place pressure on the plastic behind the back seats and it does seem to be the issue. I will have to bring it up with the dealer see if they can do anything, failing that I guess I will have to try something similar to what you did.