99 Silverado 5.3 4x4 gas mileage opinion

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by palmer_df0130, Mar 28, 2012.

  1. palmer_df0130

    palmer_df0130 Rockstar

    I have a stock(except for drop in K&N filter) 99 Z71 that has been getting 15-15.5 miles to the gallon 50/50 city/highway and the same mileage straight highway doing 80 between Yuma and Tucson, AZ. Is this decent gas mileage for my truck that has 139,000 miles on it? I got 14-15 miles per gallon towning a 4x8 Uhaul from Jacksonville, NC to Yuma. It just doesn't seem right to only get 1 mile per gallon more without towing something. What's ya'll's thoughts? Thanks
     
  2. moogvo

    moogvo Epic Member 5+ Years 1000 Posts

    Yep. Going 80 uses a LOT more fuel than 65. That sounds about right tho. I had an 03 with a 4.8 that got about 15 no matter what.
     
  3. Cujonaut

    Cujonaut New Member

    I've got a 2000 Sierra with 129k miles and I used to get about 16mpg (all city). I got some new 6x ply tires and it dropped to 13.5mpg. So what you're getting sounds about right.
     
  4. ChromeSilver02

    ChromeSilver02 Rockstar 3 Years 500 Posts

    The speed and the way you drive is the killer to mpg, my 02 silverado 4.8 gets best 18 mpg (rural) even with my heavy rims and 31" tires. If you went 60/65 mph compared to 80 your mpg would jump up, also aerodynamics and wind resistance is a big factor in highway speeds.
     
  5. mfleetwood

    mfleetwood Rockstar 4 Years ROTM Winner 5000 Posts

  6. SurrealOne

    SurrealOne Former Member ROTM Winner 1000 Posts

    This is key. When I was first considering buying a truck I looked at light pickups for mpg reasons. I then compared their mpg's to full-size trucks and noted there's really not a major difference. Trucks have the aerodynamic properties of a brick simply due to their simplistic, rectangular shapes and it definitely hurts in the mpg department.
     
  7. tbplus10

    tbplus10 Epic Member Staff Member 5+ Years 5000 Posts Platinum Contributor

    That 4x8 trailer really wont affect your mileage a lot because most of it is hidden in the shadow of the truck, and as others have already pointed out increased speed equals higher fuel consumption. You may get there faster but you'll use more fuel to go the same distance.
     
  8. Pikey

    Pikey Moderator Staff Member 3 Years ROTM Winner 1000 Posts

    My 02 with a 5.3l 2 wheel drive was getting around 24 mpg on the freeway with the cruise set at 72mph. I only had a k&n filter and a jet power programmer on it. If I did 80mph it dropped the mpg to around 22. If I drive my yukon xl like an old lady I can get 17 mpg in the city, if I drive it like I want to it drops to 13mpg if not less. Most of it depends on how hard you drive it and your rear end gear ratio. After your next fill up try driving like an old lady. Accelerate slowly and coast up to red lights rather than slamming on the brakes. I would be curious to see what the results are. You might squeeze out another 2 mpg
     
  9. palmer_df0130

    palmer_df0130 Rockstar

    Thanks gents for replying to my thread. My dad has an 03 Sierra w/5.3 and 4wd and gets around 18 highway and about the same as me around town. I will look at the link in one of the previous posts. I already drive kinda like a grandma, but not quite as slow trying to save fuel. I'll give everyones tips a try and see how much better my fuel mileage gets. Thanks again.
     
  10. JTx9

    JTx9 New Member

    I got an 05 z71 4x4
    stock 4.10 gears :gasp:

    And I got 18 driving home from Clemson on the interstate. And I get around 14 city. But then again I dont do 80 because thats like 2500 rpms lol
     

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