02 Corolla Rattling under load

Hello, did a search but it sounds like a different problem.

My brother has a 02 Corolla and it has a rattle when the throttle is down and after stops (and starts), it doesnt rattle when in Park, only when in reverse or drive.

It sounds like the heat shield is loose but its not loose at all... The sound sounds like its coming from around the belts too...

Any help would be appreciated!

Thanks in advance!