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  1. #1

    Default Very Poor Fuel Economy, Speedometer bouncing all over or not working at all

    Hello Forum,

    1994 Suburban, K2500 7.4 454 146,xxx miles

    I am having 2 different issues. First, I am getting very bad fuel economy. 7 to 9 miles per gal. I am looking to upgrade my fuel system. I am wondering if there is an aftermarket system that can go on my truck or is it better if I switch to a carb system. Then I would have to change over a lot of electronics.

    Second, my speedo is all over the place. 2 speed sensors have been replaced already, by the dealership. For this problem I am stumped.

  2. #2


    when was the last tune up? plugs, wires, cap rotor, fuel and air filters? The speedo issue could be a bad stepper motor in the instrument cluster.

    1995 Silverado 4x4
    6" BDS Suspension Lift-3" Body Lift-Add A Leaf in rear -Trailmaster SSV Shocks-Duel Steering Stabilizer Kit -AirAid Cold air intake-
    4.56 Gears with Detroit Auburn Locker-Pro-Comp Traction Bars with duel shocks-Aluminum Skid Plate Kit-38.5" x 16.5" Mickey Thompson Baja Claws-Constant Dropping fuel gauge

    2005 Yukon XL Jet Power Programmer, Bilstein Shocks, Bilstein rear springs, Helwig Anti-sway bars, EGR Window Visors, EGR Hood Shield, Denali Headlights, Headlight harness upgrade, GE NightHawk Bulbs, White Night Rear lighting system, Russell Braided SS brake lines, PowerStop Brake pads, PowerStop cross drilled and Slotted Rotors,
    2002 Silverado ext cab 2wd (Sold)
    2003 Yukon XL (Totaled)

  3. #3


    I did a complete tune up 5 months ago. Today I noticed the speedo also does not work when its cold outside, Go figure.
    I was looking at the Holley Commander 950. as an upgrade.

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