Rattle from engine compartment...how to isolate?

I've noticed a rattle that seems to come from the ICE. I can say I've heard it when the car's in EV mode, so I think it may be something loose that is tapping due to overall motor vibration. It sounds like a thin piece of metal tapping something else. Like loose paneling except metal, not plastic.

I'm not sure how to replicate this with a Prius. With a car, you can rev an engine to get the same effect from motor vibration. A Prius would require I elevate the drive wheels because I doubt you could do jack in P or N.

I've read the thread on the zip-tie fix, and I'll give it a try to see if that's what's causing the issue. I won't know until I get a chance to drive to town.

 

I found what matched the pic in another thread, but it was at the front of the engine compartment. Still, I think the rattle on that side is gone. I have another one that seems to come from the driver's side. I'd like to track that one down and do something about it as well.