OTG02

Ive got an 02 4.2 reg cab longbed stock cept for tires. Went from 255/70/16 to 265/75/16. Now here is last couple weeks my gas mileage has really been dropping. Im lucky now if i get 50 miles on a1/4 tank. Ive changed spark plugs wires fuel filter cleaned air filter check air in tires and don't see any leaks. When changes the plugs ran fine bout 3 months ago got rid of a shudder i had also plus sea-foamed after plug change. Since i didn't use motor craft plugs and used autolite platinum would that effect the mileage now. Any other ideas?? Any helps. I gotta get this figured out. Goin to be moving back to ohio in september from texas and don't wanna have to spend a 1000 or more on gas alone. Thanks for the help in advance.

blackoutoffroad2wd

Try and run some fuel cleaner thru it and see how it changes, I switched over to a 305/70/16 and only had 5 change.

Planehauler

Have you calculated in the error in your odometer with the larger tires? I think it would be reading about 5% error in distance and speed

blackoutoffroad2wd

Yeah with my speedo I'm only 3 off so I know my odometer is only off by MAYBE 5.

OTG02

Yeah im only off by 2-3.

Planehauler

I mentioned it because my truck has an error of over 13% I need to get a tuner and get it changed, then it wouldn't look near as bad.