Change rear gearing for better FE?

[Piotrsko]

Having one as a 2000 4door crew cab, anytime you are over 2000 rpm, fuel economy just plain sucks. Used to know why, but have forgotten since. So in my case I attempt to not go over 64 mpg with the tires and gearing I have or knowingly pay the mpg penalty

[cRiPpLe_rOoStEr]

Originally Posted by Piotrsko

Further research on older rangers suggests that 6 cyls got the 3.73. 4 bangers got the 4.10. My documents only cover to 2000.

After switching from the 8-valve 2.5L twin-spark to the 16-valve 2.3L Duratec, an even lower 4.56:1 rear end was fitted, at least to the Argentinian model. It was also only available with a manual transmission, and back in the day manual transmissions were more often matched to lower differential than automatics.

[E.Roy]

@hat_man stock tachs are often reporting high, say by 300rpm at redline. Being your discrepancy between 1900 rpm expected but tach showing 2,000 rpm, that overreporting could be the explanation

If you really do have 3.73, don't waste your life swapping to 3.55
I'd focus on other areas to gain FE, like aero, such as an air dam

[cRiPpLe_rOoStEr]

Aero and weight reduction can do wonders.