Check out this fuel additive

[deknight]

As a side note, here is a good website made by a Jeep owner who did actual testing to determine the best mileage.

http://www.omninerd.com/2006/07/16/articles/57

 

[MoladoGuy]

So the real method to improve fuel economy is:

* slower acceleration
* reduced top speed
* proper tire inflation
* using cruise control
* proper vehicle lubrication
* correct transmission gears
* using air conditioning only when necessary
* reducing aerodynamic drag
* removing excess weight94