ATTENTION: All Postings that advertise items for sale will be deleted from the Discussion Forum. You may post sale items for free in the Classifieds section. Sign up now.
It is a fallacy that a smaller engine, doing the same work, will produce better MPG. A gasoline engine is just a mechanism for converting the potential energy of gasoline(BTUs) into mechanical energy. Therefore, two engines, of identical design but of different displacements, both being required to produce the same mechanical energy, that is, move a vehicle of a certain weight and design, against wind resistance, up grades, etc, will burn the same amount of gasoline.
Sam is correct, actually it is not uncommon for a smaller one to use more fuel if it has to work harder. I used to own a 6 cyl 88 Dodge caravan and it actully got better gas mileage than some of the 4 cylinder dodge caravans out there.
Keep it in tune, make sure the pressure is ok on the tires, no brakes dragging is probably the best you can do.