Engine/Transmission (1998.5 - 2002) Fuel Millege

[TBohrer]

Hi, I have a 99 4x4 2500 and am lucky to get 16 MPG overall driving, sometimes 18 on the highway. I have monitered every drop of fuel since the truck was new, I keep a log. About a year ago I changed my tire size to 285-75-16 they are about 33 inches tall, with 3. 54 gears and the tall tires I must have changed the ratio enough to hurt my MPG. I like the way the taller tires look so should I go down to a 4. ll gear or would a chip pull the taller gear. Thank you R. T. B.

 

[Ramboy]

Put an EZ on it. You'll have more power and better mileage.

 

[LSMITH]

I put an EZ on my 99 and got exactly zero gain in fuel economy, it did help to pull my 285s with 3. 5 gears though. I put a VA on and gained at least 1 MPG, more like 1. 5 MPG. It will take FOREVER to pay for a box with fuel saved, not worth it at all. The VA helped pull the taller tires even better as the low end is stronger than the EZ, but don't do it for fuel economy.



For economy, check your AIT sensor, not just clean it but check it for resistive values at temps across the board.



Adjust the valves.



Put synthetic lubes in both axles and the T-case.



Air up the tires to 55 front and 50 rear minimum.



There are some more things you can do, but some trucks will be better than others no matter what.