1988 GMC 1 Ton 3+3 cab 454

Discussion in 'Member Introductions' started by JIMBOBHOG, May 9, 2011.


    JIMBOBHOG New Member


    New to this thread, but I just bought a 88 GMC 1 ton 3+3 cab truck with the 454 in it. So far I love it, drives like a dream. My only problem is that I am only getting about 7MPG without a load on it. I guess my real question is how do I get it in the 10-13MPG area. I don't raw dog it, I am not pulling a trailer with it, just picking the kids up from school and doing errands. Do K&N air filters and Lucas gas treatment actually help or are they useless? If y'all need the specs on the tranny and rear end I can pull them. I know a tune up wouldn't hurt, just seeing if anyone has some helpful hints, like putting the max air pressure in the tires(my brother swears by this trick in his 2004 Silverado) but i have no clue if he is just delusional or if it actually helps. Thoughts?? I have also read that fuel pressure regulator could cause horrible gas mileage. I have only ever worked on old Chevy quadrajets. Thanks
  2. silveradotrailblazer

    silveradotrailblazer Epic Member 5+ Years ROTM Winner 5000 Posts

    If you bought the truck I would start with the basics, spark plugs, wires, FUEL filter, cap/rotor, clean throttlebody, DON'T use carb cleaner, use a throttlebody cleaner. Change ALL the fluids and run some fuel system cleaner like Seafoam. Run the Seafoam BEFORE you change your oil so you don't contaminate the new oil . You can also use the Seafoam to clean the throttlebody and pour some in a vaccuum line to clean the upper end. Check your fuel pressure. How many miles on truck?

    JIMBOBHOG New Member

    105K. Which vac line should I pour the seafoam in. I have used it before, just dumped it in the gas tank though.
  4. silveradotrailblazer

    silveradotrailblazer Epic Member 5+ Years ROTM Winner 5000 Posts

    PCV or brake booster line.
  5. Blacksheep1

    Blacksheep1 Rockstar 3 Years 500 Posts

    He's right about keeping your tires pumped up, also take extra weight out, change all fluids to synthetic helps a little too.
  6. Vincennes02261897

    Vincennes02261897 Rockstar 4 Years 1000 Posts

    Welcome aboard and congrats on your truck purchase. I hope you're able to improve that gas millage. Good luck!
  7. mfleetwood

    mfleetwood Epic Member 5+ Years ROTM Winner 5000 Posts

  8. silveradotrailblazer

    silveradotrailblazer Epic Member 5+ Years ROTM Winner 5000 Posts

    Sorry I forgot, welcome to the club.
  9. Goldie

    Goldie Epic Member 5+ Years 1000 Posts

    Welcome to the Club! You'll find your answers here if you keep looking and asking!
  10. stephan

    stephan Rockstar 4 Years 5000 Posts

    Welcome to the club Jim. When you're doing your tune be sure & check the compression or do a cylinder leak down test. One low hole can kill your MPG.

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