Not sure why this is posted in the Gallery of the Fun Zone, but I do agree with it being in the Fun Zone.
I'd never heard of DURAMILEAGE, and Google pointed me to powerupdiesel.biz.
That site is hilarious! All the serious claims are in quotes (as in "don't hold me to it"). There are things like "Some Customers Have Reported up to 4-7 MPG INCREASE!" (emphasis theirs).
The claim about diesel trucks getting better mileage in the 90's because they have more low-end torque than the new ones particularly made me laugh.
:roflmao:
Edit: also, I love the poll!