I'm transplanting 2 amplifiers that I've been running in my Aveo into my 2016.5 Cruze and now have a new noise issue. It's electrical noise that is not engine rpm related. Everything sounds good with the key "on", but when I start the engine, there is a persistent noise like an AM station that isn't coming in. The noise doesn't get louder or quieter with the volume and does not change with rpm. When I shut off the engine, the noise remains for another 30 seconds or so until the car's computers and controllers shut themselves off then the sound is good again. I've powered the amps with both an LOC and amplifier self turn on. I've run power directly to the battery to avoid the car's circuits and still no change. I can bypass the amps completely (with speaker wires in the same locations in respect to the power wires) and then the sound is fine, just not amplified. Turning the gains on the amps all the way down gets rid of most of the noise, but limits my set-up. I've tried shielded and twisted pair RCAs. What am I missing here?