btj_S13

I've been having a strange rattling/buzzing noise heard while decelerating after mild/hard acceleration. I don't hear it after light acceleration. Definitely sounds like it's coming from engine bay. I've double checked my downpipe/exhaust. The noise does not go away when the clutch is pressed. It seems to go away around ~2500-2800 RPM. This is a fairly recently rebuilt engine, completed around ~10k miles ago.

Does anyone have any ideas on where to begin looking to fix this noise? Almost every thread i've seen while searching is transmission or diff related noises on decel, which I don't think is the case for me.