Freedom fuel additive? They say it’s supposed to increase fuel economy by up to 11%. Anyone ever try it?
http://www.freedomfuelamerica.com/

 

Has Anyone tried this stuff? What give the best mileage increase? DSL is $3.39/gal. here. This suck

 

Sorry, never tried it.

11%, I doubt it. There's more than that in the accuracy of the measurement though.

Tone ring mod, box with timing mods, max air pressure in tires, letting vehicle coast as far as possible, 285 to 315 tires, keeping rpms below 2000, drive it like a diesel truck (slowly).