Lazarus Long

I was on a road trip in my 98 vert, M6. Conditions were cold (mid 30s) and windy. As I passed a semi, I heard a loud bang, then a loud mechanical sounding reverberation as f something came loose and is rattling around.I stopped on the side of the road to check things out. My first thought was the truck threw something into the side of the car, but there was nothing.

My next thought was maybe a tire, but they were fine and pressure good.

Another thought was the rear window in the top came loose and blew out, but it is. also fine.

I started out again, and I'd wasn't getting the loud mechanical banging/rattling, but I have still have a low level vibration or reverberation going on. The car drives and rides ok.

The convertible top seems like the most likely culprit but it seems ok. No codes or messages in the DIC.

Any dead of what to look for? I think the semi was just coincidence.

Lazarus Long

Further info: I was not accelerating when I passed the semi. I was on a dual carriage way with the cruise control on. I was simply maintaining my speed and passing on the left. When the bang occurred, the driving characteristics did not change - did not pull either left or right, loose power, shimmy, or steering change. It was just a loud bang and then it felt like something came loose and was rattling around. It felt like it had something to do with the top
If it is, I can't figure out what it could be. I unlatchd, raided and .lowered it. It works like it should.

Lazarus Long

Update - I think I found the source of the problem: