Electrical impacting Car Stereo

[33fromSD]

Hey All

With the engine running has anyone notice bad feedback (popping, static, crackling) through the speakers when playing their stereo? With the engine shut off everything sounds fine, no feedback.

I have been chasing this issue from day one of installing it.

Things I've tried to resolved the issue:
1) I have tried three different (as in different brands / types) of stereos, all three result in the exact same issue

2) I have ran power & ground back to the battery to separate the power / ground from the power & ground in the wire harness from FFR.

3) I have completely rerouted my speaker wires. Originally they ran along the trans tunnel in parallel with the rear wire harness, but I re-ran them under the car on the passenger side where there is no electrical, so the only electrical power they come into proximity with is the power connection on the back of the stereo. I have then separated the power from the speaker wires on the back of the stereo.

4) I have tried several different antennas, as well as several different antenna locations (all away from any of the wiring)

I'm at a loss, I've installed dozens of stereos in my life and have never ran into an issue like this before.

Thoughts / ideas?

Thanks in advance.

Jim

[Additional Edit]
This is a simple install by the way with power, ground, front & rear speakers and the antenna (11 connections), there is no amp, no sub woofer, etc.