Aftermarket Audio System Broke My Car?

[PityOnU]

I have done quite a bit of troubleshooting. I've ruled out everything you have mentioned, but power source. I am confident that if I were to power the amp and receiver with a separate dedicated power source it would work fine with no issues. The issue is somewhere in the electronics in the Mirage. Something blew and because of that it's creating feedback noise. It wasn't doing this before said thing blew.

Hm, I see.

Afraid I can't help much other than linking to this thread which itself has links for the service manual and wiring diagrams for the Mirage. I will say that I'm surprised to see that the radio is hooked up to so many different systems in the car. The Mirage does use CAN bus for communication, which definitely adds noise to many of the lines.

Perhaps a filter capacitor blew somewhere? Where it would be is anyone's guess, though. And it must be an extremely localized event if it did - I can say from personal experience that the Mirage is rather touchy with any lines it sends signaling across. Any additional noise would interrupt communication and your car would be throwing engine codes left and right.