Can anyone give me any help on how to make my 2001 GMC 2500 HD with an 8.1 get better gas mileage.

 

Easy don't drive it!

 

Had that same truck for 50000 mile averaged 14 to 15.3 highway 9 to 12 depending which trailer i was hauling.best advice put a tuner in, K&N air filter ,stick with stock size tires,stay out of the throttle,good truck ,good power.my new one is a 2006 LBZ

 

get an intake and cat back and a custom tune requesting for better MPG.