To me, I would have thought that a dirty fuel filter would somehow increase fuel economy from restriction of fuel flow so less is burned or whatever. I changed the fuel filter in my 96 Sunfire, and doing the ol' blow-through-the-filter test, the old fuel filter was quite restrictive. The new filter, a FRAM unit BTW, was quite a bit less restrictive than the old one. So that's supposed to increase fuel economy somehow? We'll see how it goes I guess.