I have a low mileage 2004 Mustang convertible. At speeds above 60 mph I have a recurring rattle/popping sound behind the rear seat. It sounds like a wind leak of some sort. The plastic rivets holding the trunk lining in place are loose, so i have suspected wind is somehow finding a way into the trunk and causing the popping/rattling sound at higher speeds. I padded one of them, but this persists.

Any clues?

David