Better mpg on Chevy 350 TBI

Discussion in 'Trucks and Trailers' started by zz4guy, May 1, 2007.

  1. zz4guy

    zz4guy LawnSite Senior Member
    Messages: 901

    I've got a 92 K2500 with the 350 and TBI injection. Right now I get about 10mpg in the city and 13mpg if I'm lucky on the highway.

    Is there a way to improve the mileage at ALL? I've heard of people advancing the timing on these motors to improve mileage. Does that work? I can already tell the motor has lazy timing. Any other ideas? THanks.
  2. grassmanak

    grassmanak LawnSite Senior Member
    Messages: 792

    not to many things you can do on a gas engine, make sure your oil and tranny fluids are fresh, clean air filter also.
  3. zz4guy

    zz4guy LawnSite Senior Member
    Messages: 901

    The thing is I get 20mpg in my camaro on the highway with the same motor and gearing with a carburetor. I'm not worried about city miles- I know they will suck. But why cant I get good highway mpgs? It's a real downer when I see something I want 300 miles away and figure I have to shell out $200 in gas :confused:
  4. grassmanak

    grassmanak LawnSite Senior Member
    Messages: 792

    buy a 02-04 diesel if you want 20+ mpg
  5. Eclipse

    Eclipse LawnSite Bronze Member
    Messages: 1,149

    Aerodynamics, 4x4, and level of fueling.
  6. hosejockey2002

    hosejockey2002 LawnSite Bronze Member
    Messages: 1,195

    What he said. Your 2500 probably outweighs your Camaro by 2500 lbs. or more, and comparably has the aerodynamics of a brick. Is that mileage towing or solo? Also, big tires or a heavy foot will kill mileage.
  7. Sydenstricker Landscaping

    Sydenstricker Landscaping LawnSite Bronze Member
    Messages: 1,281

    On my 94 GMC 2500 with the 350 V8 TBI, I got really bad gas milage as well. I put a k&n air filter on it, complete tune-up, ran some injector cleaner through it, and a flowmaster dual exhaust. The stock system chokes back that 350 so much that you need to open it up. I got about 12-13 in the city and 16-18 on the highway after that. And it was 4x4, 3 inch body lift, and 33 inch BFG all terrains!!!
  8. lawnboy dan

    lawnboy dan LawnSite Gold Member
    Messages: 3,711

    dont feel bad -i get 10 mpg from my 93 1500 with 305 while towing and its bone stock. my neighbor has 88 1500 w/350 with all the mods-no cats-flomaster -k/n he gets 12 mpg not towing anything- mpg isnt these trucks strong suite!
  9. mcwlandscaping

    mcwlandscaping LawnSite Gold Member
    Messages: 3,163

    Ive got a 97 k2500 and have come to accept the lousy gas mileage as it makes me money. I will soon be doing some work like Tom described above to improve mine.
  10. General Landscaping

    General Landscaping LawnSite Senior Member
    Messages: 801

    From years as a mechanic, I can tell you there are good ones and bad ones.
    Two vehicles with the same everything can be very different in the power & mileage department. It's not always a trade off.... some of them have economy and power.
    It seems to be something in the engine machining/measurements/setup..... hard parts.
    I've tried to swap over bolt-on parts to try to change things, but it seems to be something it's "born with".
    A friend of mine has a Tahoe, 4X4, 5.7L with Buckshot Mudders that can pull a trailer and get better mileage than I can get bobtail in my Dakota 4.7 4WD.

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