Newbie Here --- 6.0 Liter V8 -- 2500hd --mpg ?

Rickey70 · March 24, 2009

Last weekend I bought my first GMC. Its a 2003 Sierra 2500HD and has had a 6" lift installed with 315 X 75 X 16 tires added. I know that the speedometer will be off and according to my GPS Navitagion, it's off by approximately 5-7 MPH. I also know that the MPG will inaccurate. I'm wondering if anyone has the same truck with the same lift and if so, what kind of mileage are you getting? I am planning to tow a 18' toy hauler (that too is a recent purchase).

pennzoil29 · March 24, 2009

Welcome aboard

Draenor · March 24, 2009

I'll guess......

10mpg hwy 8 city..

...Have you re-geared?

REV353 · March 24, 2009

I agree 6-8mpg. That 6.0 might be worse mpg than my 8.1. Food for thought. I was getting 8ish until I changed my plugs and wires. I installed Autolite Iridium plugs and Taylor 45-50 ohm per foot wires, now I am getting 12 plus, on the hwy and over 8mpg towing. Sweet truck though.

rvsahs · March 24, 2009

Welcome to GMT!

DofD · March 24, 2009

Hey there and welcome to GM Trucks!

99silveradoz71 · March 24, 2009

Welcome

bigredmariner · March 25, 2009

Nice truck, Welcome to the forum.

BuckFeverZ · March 25, 2009

Welcome to the site.

If you're worried about gas mileage, you shouldn't have bought that truck.

GARB55 · March 25, 2009

Welcome, don't look at the gas gauge while towing! Nice truck! welcome

Rickey70 · March 25, 2009

I'm not worried about the mileage (my wife thinks i'm nuts for saying that). I was just wondering how often I needed to plan to stop and fill it up.

I was told when I bought the truck that is had a superchip in it, but i'm finding that hard to believe as the speedometer is running 5+ mph slow. But is sure is nice having that power under the hood when the gas pedal is punched.