You folks need to try Lucas gas treatment. (No, I don't own stock in the company.) It costs $10.00 for 5 tank fulls and you get 40-50 more miles per tank.
I honestly did not believe you as I have tried these things before with very little effects, but I just got 2+ more MPG on my last trip using the Lucas Fuel system additive, thanks, I will be trying this out some more.