98 Burb

[Gregz]

I have a 1998 gmc 2500, shes got 190k on the clock, but it runs and looks awesome. I have on little problem, I never get better than 11mpg. I have the 5.7 vortec, yet I hear the guys with 454s are gettin about 14 hwy, what am I doin wrong? all the maint is current, she purrs like a kitten, but i sure would like to get a cpl more mpg out of it

 

[redthies]

The bigger 454 isn't working as hard as your 350 is. I would think you should do better than 11 though. Do you h ave a lift and big tires?

 

[Gregz]

33 inch tires, 4 inches of lift

 

[98dango]

Ding we found your problem. 33s and the lift will drop your mileage. Is your speedo calibrated for the 33s it came with 29" tires. Also is the trans shifting alot i had a 98 p/u on 33s and it was hunting for gears way bad.

 

[Gregz]

na the trans isnt shifting much, I listen for it and watch my tach. well Im thinkin of gettin a s10 blazer as a dd and doin a mild build to the burb. Im very happy wih the gearing, lift ires ect, the g80 locker. My goals are to fab new bumpers, a winch, and better cargo storage, probably a roof rack as well. Livin in wv theres hundreds of miles of trails me and my 4 yr old and my grandkids go on. ( yep 4 yr old and grands, oldest boy is 24)

 

[98dango]

Sounds good and on mileage there are tons of factors but lift never helps. I would also check simple things like tune up make sure the timing is right.