[zeptoplix]

Defintiely sounds like a problem with the ground. What condition is your head unit in? are you sure there is no loose connection ? and there exactly do you have your ground wire running to?

 

[zeptoplix]

I have never heard anyone using that method. What I would do personally is get some self tapping metal screws, Or drywall screws work great, pick another area and just sand the hell out of it, brush it off (until the metal is very shiny) brush it off, and try grounding it there. Otherwise your probably looking at a hardware issue with either your deck or your amp.