For all you inclined, I figured out what the hell the vibration is and I'm sure it will take care of all the guys and gals with the same issue. Today turned out to be a beauty of a day, nice and warm and sunny so I started rootin' around inside under the dash tugging and pushing on things and it turns out not to be the gas pedal at all!! It always struck me as something with weight to it and sprung, so I start jerkin on the brake pedal back and forth and side to side and discovered enough movement side to side on the pivot point up by the firewall. So when I look way up by the the arm I see the fairly large return spring which explains the "sprung" feeling when it starts.....now I'm gettin excited, I hop in and go for a rip down the fishing hole road which has a fair amount of washboard. I start into the washboard and let it do its thing, same old rattle that you feel through the gas pedal until I hook my left foot behind the brake pedal and gently pull back towards me and......There it is, Gone, I repeated this several times on the washboard and absolutely no noise, I couldn't feel the vibration in the gas pedal whatsoever.
Givr' a Try!! and then you can tell me I'm full of shit....lolol