GM Diesel Fuel Mileage

Discussion in 'Performance & Fuel' started by dwill3015, Nov 30, 2008.

  1. dwill3015

    dwill3015 Epic Member 5+ Years ROTM Winner 1000 Posts

    Our number of members owning GM diesels are growing everyday. What year and version of GM diesel do you own, what is your average fuel mileage, and what mods have you done to improve it?

    I have a Duramax LBZ in my 2006 Silverado. My average mileage is 16-17in the city, 19+ on the highway with a 6" lift running 35's and 3.73 gear ratio. I have added 5" Diamond-Eye cat-back exhaust, a modded stock air box (breathes better than stock) and a Godzilla Stealth2 programmer set on 70hp tune (best mileage with this setting).
  2. CaptnBud

    CaptnBud New Member

    Average 14 around town, Maybe 15 on a trip with any luck. 14,000 miles, 10k was an around the country in the spring pulling a 30' Coachman averaging 9.5 - 10 mpg. 2008 LMM completly stock. I can't justify Voiding thr Warranty.
  3. Nem

    Nem New Member

    thought they would give better mpg than that....
  4. dwill3015

    dwill3015 Epic Member 5+ Years ROTM Winner 1000 Posts

    Mine is still under full warranty. My service manager at the local chevrolet dealership told me that programmers are great and recommends them but anytime the truck is brought in for service, return it to the stock tune in case the ECM needs to be updated. Once out of the shop, I hook the programmer back up and install my tune etc. My exhaust is cat-back so i have not changed my warranty there either.
  5. phoebeisis

    phoebeisis Epic Member 5+ Years 1000 Posts

    Wow, 19mpg highway with a 6" lifted 7000 lb 4x4 truck is very, very good. 16-17 city is even more spectacular.

    My 98 Suburban-2wd 5.7- gets 20-21 mpg hy but 12-14 mpg city. It is maybe 1500 lb lighter, 2wd, isn't lifted,and has tiny 235/75 15" tires/wheels.

    I would have never guessed a 3/4 ton 4x4 with a lift could get more than 16mph highway and maybe 11mpg city.Especially with those kinda aggressive looking tires-aggressive tires usually hurt mpg.

    Pretty good mpg.
    Nice looking truck also.Wanta' trade!!??


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