GM Truck Club
Founded in 2004 ~ We're the #1 Chevy Truck & SUV Forum.
Silverado & Sierra | Tahoe & Yukon | Suburban & Yukon XL | SUV & CROSSOVER
Results 1 to 5 of 5
  1. #1

    Default Silverado MPG Computer in Truck

    Hey guys, I recently got in an argument with someone about this. I understand the math related to how the fuel economy is calculated, using MAF and fuel-flow and such, but what I want to know is, how is it calculated overall? In my 2008 Silverado 2500HD with the 6.0 Vortec, when I reset the Average Economy, Trip, Miles used, etc. I find that my average economy jumps up and down, from 22.0 MPG to 7.3 MPG. My friend tells me I'm wrong. He says the fuel economy is calculated independently each mile, regardless of what the previous mileage is. However, I think that it averages all the mileage overall, unless it is reset. This might not be very clear, but I hope this helps with an answer.

  2. #2
    TRPLXL2's Avatar
    Join Date
    Jan 2009
    Norwalk, Ohio
    Blog Entries


    There is no way in hell it would read 22mpg with the 6.0 motor, not even at idle would you get that kind of gas mileage on that truck. I think you have an electrical problem if it is bouncing around like that, mine would change but not that radical. It would go from 14.0 to 14.3 and back down, and that would be over a 100 mile trip. I have also gotten into arguments over this same issue with guys at work, I really don't think the DIC is accurate.
    2004 Chevy Colorado
    LS1 5.7 swap/TBSS rear axle swap

  3. #3
    Jr. Apprentice
    Join Date
    Mar 2009
    Kennebunkport Me


    I don't have a computer in my truck, but based on the computer in my wife's Toyota, you would definitely see a lot of variance when you first reset your computer. The more miles you drive the less variation you'll see. It would not surprise me at all to see 20+ when you first reset it. If you have an instantaneous MPG function you will see it all over the place, I've seen 30 or 40 mpg down to 2 or 3 at any given time. The overall average is based on the miles driven and the number of mpg calculations it takes during those miles.

    That's my 2 cents, for what it's worth!
    1996 K2500
    6" Superlift
    33's Freakin Maine made me remove my 35's
    Air Raid Intake
    CAT Back Exhaust

  4. #4


    If the truck is idling, the MPG would be 0, you are using fuel and going nowhere.
    According to manual, the average is calculated from last time of reset.

    XS ive1:(^^^)
    2008 Silverado Crew LTZ Southern Comfort conversion
    SoCo cat back duals
    Volant CAI
    6" Pro-Comp lift
    ARE cap with Yakima rack system (winter)
    GM Hard tri-fold tonneau (summer)
    GM rear wheel liners

    XS ive2:(avatar)
    2014 Silverado 2500HD CCSB LTZ Z71 6.6 DMax/Allison
    6.5" BDS 35" Nitto Trail Grapplers
    LineX/wheel liners/OEM tube steps/sunroof/slider/mirrors/Nav/cablights/trifold tonneau

    Getting the toys to the track with a 2007 Roadmaster 7X12 V-Nose 7k tandem "Mobile Man Cave".

  5. #5

    Join Date
    Feb 2008
    Red Wing, Minnesota, United States


    My 1995 GTP had a setup just like that and I could use it for instant economy or life of the car, and you could reset the life mpg and then it just starts over from the moment of reset. When using my instant eceonmy I could get readings anywhere form 38 to 7mpg. And yes that it is possible to pull 22 mpg on a 6.0. IMO those are actually pretty accurate little computers, the one in my GTP was always nuts on when I would do the math myself.
    99 K1500 Suburban LT "THE BEAST"
    Hypertech III, K&N, true dual

Similar Threads

  1. Computer in an '04 Silverado
    By smccollamjr in forum General Chevy & GM Tech Questions
    Replies: 2
    Last: 01-20-2010, 09:47 AM
  2. Bad Computer??
    By ronbway in forum General Chevy & GM Tech Questions
    Replies: 2
    Last: 08-16-2009, 03:12 PM
  3. computer mod
    By andrejj in forum Chevy Colorado Forum (GMC Canyon)
    Replies: 9
    Last: 04-05-2007, 10:11 PM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts