06 crew cab ground loop whine

[tdrumm]

I just installed a two amp system in my 06 crew. Now I have a very slight ground loop whine out of all four door speakers. The amps are mounted to a piece of mdf which is screwed to other pieces of mdf glued to the back wall of the cab with carpet sandwiched between. The power runs down the driverside rocker to a dist block mounted on the same piece of mdf as the amps. The RCAs run across the trans tunnel in the center of the cab, the speaker wires run on the driverside floor pan midway between the power and RCAs except the right rear door, which runs on the right rocker. The ground also has a dost block on the mdf, and the main ground was originally tied to the factory ground stud on the pass side C pillar with the defroster. I then moved it to its own location near that stud, and then to another spot by itself at the base of the C pillar. The sound is still there. What could be causing this noise? How can I fix it?

Here's a pic of the main ground now.
http://img.photobucket.com/albums/v75/tdrumm/5643a2c9.jpg

[thethickster]

What kind of spark plugs are you running? Some hi-performance plugs are non resistor. Im no expert in car audio but ive heard of non resistor plugs causing interference.

http://www.ngksparkplugs.com/techinfo/spark_plugs/faq/faqresistor.asp

[tdrumm]

Stock plugs