[pvpman22]

One of my family members made the original post about the issue I'm having.

Few Clarifications:
-Replaced the alternator with another used alternator from Ebay
-Replaced Belt
-Replaced 2 Smooth Idler Pulleys
-Replaced 1 Grooved Idler Pulley
-Replaced Tensioner
-Manual Transmission for the 2017 Series Yellow BRZ

I find that the rattle comes one after the car warms up after a cold start. Also, it's more obvious when the AC compressor clutch engages, but I found any large electrical load brings the rattle back (Ex: I turned off AC but then turned on seat heaters and defrosters and rattle came back).

I usually can only hear the rattle that comes and goes while idle sitting at a light.

I was going to try to track down where the noise is the loudest using a Mechanic's Stethoscope and possibly going underneath and removing the shield and seeing if I can find anything rattling around...