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  1. #1

    Default 2008 hd2500 6.0 gas

    Hello everyone I am Donnie from South Carolina. I have is 2008 hd 2500 6.0 gas truck with 40,000 miles and has terrible gas mileage 9-10 mpg..I have always have had chevrolets.I need help with gas mileage without sacrificing any power loss. thanks everyone

  2. #2


    Welcome!! Thats odd because our 07 2500 gets 14-15 highway and 12-13 in town.

    2006 Duramax LBZ
    Edge Evo
    4'' Diamond eye to 6'' tip
    16'' ion alloy, 33'' fierce attitudes
    Lots of work left to do!

  3. #3


    Welcome to the site. Good to have you on here. You'll probably get a lot more hits on your question if you put it in the performance and fuel section further down the forum page. That being said, do you have any other mods? Lift? Tune? Lead foot? What kind of driving do you do? Highway? City? Does it idle a lot? I know most of those things are pretty obvious, but they can add up FAST when it comes to reduced mileage.

    To Be Completed (Eventually):
    6" BDS Suspension lift | KingShocks Front and Rear Coil Overs | 4.56 Gears | 35" A/Ts (TBD) | Cervinis 07-12 Silverado Ram Air Hood | Fab Fours Front Winch Bumper (CS07-H2051-1) | Fab Fours Full Size Rear Bumper (CS07-W1850-1) | RX-2 Series Main Grille (Black) | Line-x Bed and wheel wells | Skid Plates | Rizor Automated Tonneau Cover | Custom Bed Insert | RBP RX-3 Series Nerf Bars | Kenwood Excelon DNX9990HD | JL Audio Stealthbox (2x500RMS) | JL Audio HD 1200/1 Class D Mono Amp | JL Audio C5-653 Components (Front) | JL Audio C5-650 Components (Rear) | JL Audio Slash v2 300/4v2 Class A/B Amp

  4. #4
    Master Mechanic
    Dirty Dog's Avatar
    Join Date
    Mar 2012
    Regina Saskatchewan Canada
    Blog Entries


    Welcome to the club and enjoy the site........

  5. #5


    Thanks guys for the welcome,my truck is a all stock 2008 hd2500 6.0 gas crew cab z-71 with 305/70/16 km2 BFGs.11.8 mpg with bicycle tires 265/75/16.. 10.3 mpg with the bigger 305/70/16. just looking for better realistic gas milage--- 14-16 highway.i can do the intake and exhaust.Even a programmer if there was one that clearly made a difference.I have owned the truck for 2 1/2 years and only put 9000 miles on it because of the gas mileage issue.thanks for all the help

  6. #6


    We are the Borg. Lift your vehicle and surrender your keys. We will add your biological and technological distinctiveness to our own. Resistance is futile. Erm, I mean ... welcome to GM Truck Club! In addition to exhaust I definitely recommend a custom tune using a programmer. You'll get more out of that than a stock tune from the same programmer...

  7. #7


    Welcome to the club Donnie, good to have you as part of the team. I agree with the programmer, the exhaust and the intake are the first things people normally do. I got the Edge CS programmer, K&N intake and Magnaflow exhaust and I get 17 and 19 and i can get 20-21 HWY doing 65 with the cruise.

    2002 Chevrolet Silverado Extended Cab SportSide: See Mods in My Garage

  8. #8
    Sr. Apprentice
    Join Date
    Mar 2009
    Ballwin, MO


    Will any of these changes cause an issue with the warranty?

    Nevermind found the thread.
    Last edited by Brews; 04-24-2012 at 11:41 AM.

    The memories of a man in his old age, are the deeds of a man in his prime.

  9. #9

    mfleetwood's Avatar
    Join Date
    Jul 2010
    Denver, CO
    Blog Entries


    Welcome to the Club!!!

    Here is another thread that contains ideas on how to improve mileage.

    Mike (Denver, CO) - 2008 Sierra 1500 Z71 SLE 5.3L 4WD

    SUSPENSION: Rancho 4" Suspension Lift; Rancho RS9000XL Shocks; Rancho Skid Plates; Rancho MyRide Wireless Shock Controller;
    BFG All Terrain KO 315/70/17
    DRIVE TRAIN: 4.56 Gears; Detroit TrueTrac Differential; True Cool 40k Transmission Cooler
    PERFORMANCE: DiableSport Predator Tuner; Custom Tuned by Diablew; Magnaflow Exhaust; AFE Cold Air Intake
    ELECTRONICS: Kenwood DNX6180 Touchscreen; Subthump box w/10" Kicker; Driver Information Center (DIC); Rear View Camera
    ACCESSORIES: Westin Brush/Grill Gaurd; Westin Nerf Bars; Truxedo Tonneau; 20% Tint; Tow Mirrors w/Heat & Signals

  10. #10


    Welcome to the G M T C !

    2010 Z/71 Colorado C/C
    Black 4X4 w/5.3L V8
    2007 Winnebago Adventurer
    w/8.1L Chevy & Allison 6spd.
    Canyon Lake, Texas

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