...or sometimes when turning the enngine off. seems tha something is shacking, like for example the plate holder, or a badly fixed seat. anybody heard before?

Maybe flaps in the air vents behind the rear bumper? I can hear them rattle sometimes on my Yeti, when I close last door.

This (or something very similar) has been discussed here. Its generally a rattle on the striker plate.

hard to say, would say somethingh rattle close to the bumper rather doors, but could be wron. the noise has a tail, it...bumps!

" Does it sound like a Golf "