6.0 liter bad mpg

May 07, 2005 6 Replies

I have a 1999 silverado 2500 with the 6.0 liter and im only getting about 9 mpg. Is this normal for this engine or is there something wrong? I have noticed there is a strong smell of unburned fuel from my exhaust but there has been no check engine lights come on from something like a bad o2 senser or anything else that is monitered by the computer. If you have any suggestions please tell.



The 6.0`s are terrible on mpg. I have an '04 and I get mostly 12,but If I`m hard on the pedal,I get maybe 10 max. How many miles do you have on your truck? Are you a lead foot?

I have an 04 GMC 2500HD ext cab shortbed and get about 12.8 around town, 14 with all highway driving unloaded. I don't know about mileage pulling a load. I am a fairly aggressive driver.

HTH, Jeremy

'02 2500HD witha 6.0 got 9-11MPG avg and 6-8 doing some decent towing in the bed only.

Thanks for the reply and yes I am a little bit of a lead foot but now that I get such bad mpg I have learned to let off . I have 720000 miles on the truck now.

Thanks for the reply and I was a leadfoot but not much of one now with such bad mpg. My truck has 72000 miles on it.

I have an '03 2500HD 4x4 with a 6.0L, and unloaded I get between 13-15 mpg mixed highway and city (approx 75% - 25% repsectivly).

Depends on the time of year (winter I get worse because of the formulation change and 400lbs of sand bags in the bed ) and I have a tonnau cover.

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