Unrelated, but related.
The floor on our 2003 and our 2004 avalanches would pop, loudly, and you could feel it in the floor of the cab about like a softball size rock hit it at 50mph.
It was the passenger side hood hinge bolt.
How it rattled the floor no one knows, but it was a common problem in avalanches and, assumable, silverados. I Added 10ftlbs to the bolt, no more noise or bang.
Look where the other poster said because it is historically known and makes perfect sense, but rule out nothing.
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