Welcome to the Zone!
Best way to get good MPGs out of a SUV is like what Ron said, keep it tuned, Always have a clean air filter, proper tire pressure, don't keep unnecessary weight in the back, and (I don't know if this works for any other Bronco besides mine, but) learn where the Bronco likes to shift Thus using a higher gear and lower RPMs.. You can get great gas mileage by hanging out at those magic speeds. I know that in the city I can do 24-26, and 37MPH and only turn a 1000 RPMs. Thats better then my '99 Expedition. Another thing too (and this could be considered as pert of keeping a tuned engine) but make sure that your throttle cable isn't stretched. Nothing worse then low air intake because the throttle body isn't opening up.

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