early 99 gmc slt 1/2 ton ext. cab short box with 5.7. I am only getting like 12 to 13 miles per gallon. I gave it a tune up, fuel filter, air filter and still cant get any better mileage. Just curious on what others are getting with their trucks. When I bought this truck I was expecting atleast 16 or more. :runaround:

Yup thats pretty much the norm for me 12-13 mpg.there is alot of metal being moved around, less weight more mpg.

Oh well i guess. Has plenty of power and thats all that matters.:tongue:

There are a lot of things that affect fuel mileage. Oversize tires and wheels will throw off mileage as the speedometer is no longer accuartely recording miles + wider tires have more resistance to roll and weight more. If the truck has any non-stock equipment, that could lower mileage, carrying around extra weight will lower mileage. How you drive can affect mpg, if you take off fast, drive fast etc, all will lower the mpg.

IMO that is typcial for around town driving.

I get 11.5 city driving. about 18 hwy.