It does sound pretty bogus.
Originally Posted by czar99
less RPM's at highway speeds.
That's mechanically impossible. To go X speed, the engine and transmission always have to spin the same speed regardless of engine efficiency, short of swaping out gears.
If you want to save gas, accellerate slower and cruise at a lower speed. Putting magnets on your fuel line won't do anything to the milage, but it is an amazing placebo.