ratting sound in rear hatch area

[luey2011]

i am trying to figure out the rattle sound I hear when I accelerate from a stop to about 2200 rpm while shifting from 2nd and into 3rd. it doesnt last after getting going in 3rd. sounds like aluminum panel vibration. definatly sounds like its in the rear hatch area.
what ive done so far: removed the rear hatch side panels, added some weatherstrip in an area where I noticed vibration with the gas tank plastic cover hitting the lower bottom of the body, confirmed it wasnt the rear glass hatch vibrating as well. these didnt help.
the car is assembled and ready for body/paint however the interior soundproof and carpet is not yet in and some of the aluminum panels that get installed after paint are still not installed.

any suggestions? I know its hard to explain.

[Brandonk603]

It may be silly idea but could you have someone drive the car while you get in the back and try to duplicate the noise? If your laying back there it may be a lot easier to isolate using your hands to press on panels.
Good luck!

[Cincy123]

We had a suspension noise on the rear end of our coupe that was driving us crazy. Turned out to be the rod ends for the UCA on the IRS that FFR supplies were junk. Replaced right and then left rod ends and that took care of it. Several threads about this on the forum. I think I ordered mine from FK bearings.

[UpNorth]

Could it be one of the two small panels riveted to the floor at the back over the tank?
Or the fuel filters over or around the tank that are just a lttle loose?
Just my 2 cents...