1998 Chevrolet Blazer 4-Door LT
Annoying rattle underneath the passenger side of the car had the blazer jumped the other day by insurance company and the guy said it was the heat shield.

 

Quite possible. Have you gotten under it to check?

 

I ask because I had the same thing for weeks. I crawled under and messed with the shield, looked for dropped tools and ultimately had the ball joints done, which it needed, and still the rattle persisted. Finally heard it one day when I was driving with the hatch open and it was a loose slide adjuster bar on the luggage rack. I swore it was the front passengers side.
Maybe??