OK, so I followed the Ashhong tutorial like a lot of others before me to replace the factory head unit with the avic d3 using the metra harness to connect with the factory amp. I'm having some sound problems though (cracking/fading in and out). Most things seem to be working fine. Navigation is tracking, radio signal is good, dvd/cd's play, but the sound is off. I've re-checked the wires and can't find anything loose. Can someone offer an explanation as to what wires might affect the overall sound quality? I consider myself pretty technically savvy , but I'm no car stereo expert. Could a poor ground lead to my problem or is there something more?
Any advice would be appreciated.