gas tank full of crud, pick up screen getting clogged, and my favorite crud in the line from tank to FP. The extra head weight of a full tank may ease the situation. 16 mpg sounds about right for webers in city driving, get a little better than that in town with my SUs but U have a very heavy foot and a hilly comut, can get 30 mpg hwy though. From what I have read, Webers are at best below par with SUs re milage/performane/reliabilty but much worse if not tuned properly.