+ Reply to Thread
Page 1 of 2 1 2 LastLast
Results 1 to 10 of 20

Thread: MPG drop....

  1. #1

    MPG drop....

    Just wondering, I got my truck back in November. Since then I have put on a little over 7000 miles. I was getting around 16.5-17 mpg for the first month. I was told after the engine breaks in, I would prob see better.

    Well, I have checked my gas milage the past 3 tanks and the highest I have got is 15.3 or so. I have put on exhaust, and know most people get a little more heavy on the pedal to hear it, but I dont find myself doing that much. I actually played the "2000 game" last tank, and that was my highest mpg at 15.3.

    NOTE* I havent checked my tire pressure, and havent changed my air filter.

    ^^Could this be why my mpg is dropping?

    I have a SLP closed intake coming in tomorrow and will keep track of the mpg increase/decrease.

    I hate to ask stupid questions like this, but I am just seeking advice. Thanks in advance!

  2. #2
    Join Date
    Mar 2003
    Location
    San Marcos Texas
    Posts
    4,393
    Tire pressure makes a huge difference in my trucks!
    2006 Superior Blue Trailblazer SS AWD, Stock as a rock

    Sold: 2002 GMC Sportside Denali front end with a 2002 LS1, FLT level 5, Yank 2600, Trick Turbo, T76, Nelson intercooler, 60LB injectors, Warbro fuel pump, Eaton locker, Magnaflow, 3.42, Nelson Performance Tuning (speed density).

    Sold: 1981 GMC LB RC 1500 2002 4.8L 4L60E 12 bolt 3.73 Richmond Lock Right AC PS Nelson Performance tuning

  3. #3
    Do you run it at the recommended pressure on the inside of the fuel cap?

  4. #4
    Join Date
    Mar 2003
    Location
    San Marcos Texas
    Posts
    4,393
    I hate to say but no! I run what the sidewall max is or higher. I however do not suggest that you run anything unsafe (disclaimer).
    2006 Superior Blue Trailblazer SS AWD, Stock as a rock

    Sold: 2002 GMC Sportside Denali front end with a 2002 LS1, FLT level 5, Yank 2600, Trick Turbo, T76, Nelson intercooler, 60LB injectors, Warbro fuel pump, Eaton locker, Magnaflow, 3.42, Nelson Performance Tuning (speed density).

    Sold: 1981 GMC LB RC 1500 2002 4.8L 4L60E 12 bolt 3.73 Richmond Lock Right AC PS Nelson Performance tuning

  5. #5
    Join Date
    Nov 2003
    Location
    Denton Texas
    Posts
    20,540
    Gas mileage drops as you add weight to the truck, too. Be sure you check the mileage through the same methods and routes if possible. Try 93 octane vs. 87 octane. Lowering the truck often helps the MPG due to less air under the chassis creating drag.
    See my truck data in the "My Garage" section here... http://www.ls1truck.com/forums/my-ga...tml#post191709

  6. #6
    Join Date
    Sep 2007
    Location
    Texas
    Posts
    5,301
    what size tires?

  7. #7
    Quote Originally Posted by GMCwantsLS1 View Post
    I hate to say but no! I run what the sidewall max is or higher. I however do not suggest that you run anything unsafe (disclaimer).

    Im so going to run them way high and YOU are the one to blame haha jk.



    Quote Originally Posted by RedHeartbeat View Post
    Gas mileage drops as you add weight to the truck, too. Be sure you check the mileage through the same methods and routes if possible. Try 93 octane vs. 87 octane. Lowering the truck often helps the MPG due to less air under the chassis creating drag.
    Yes, my conditions are 90% the same. Varies very little. I ran 93 last time


    Quote Originally Posted by ChevyLee View Post
    what size tires?

    Sadly the factory **** tires. GENERAL 245/65/17 I believe. WORST TIRES EVER MADE!!!!I can squeel the front ones more turning into a parking spot than a lil honda can off the line. hahaha

  8. #8
    On a side note, just for giggles, I filled up right before I came home from downtown.

    60 miles an hr, about 5 lil stops in the city, and 33 miles later...I filled up again.

    18.77 mpg. This is a nice number, but this was just for giggles. The other data is from my "average" driving.


    Hopefully after I get the SLP intake on tomorrow, next tuesday night on my way home from school ill do the same thing and see if the strait 33 mile trip has any diff.

  9. #9
    Join Date
    Mar 2003
    Location
    San Marcos Texas
    Posts
    4,393
    Also wind makes a huge difference. A strong headwind can eat up 2-3 MPG easy. Try drafting behind big trucks.
    2006 Superior Blue Trailblazer SS AWD, Stock as a rock

    Sold: 2002 GMC Sportside Denali front end with a 2002 LS1, FLT level 5, Yank 2600, Trick Turbo, T76, Nelson intercooler, 60LB injectors, Warbro fuel pump, Eaton locker, Magnaflow, 3.42, Nelson Performance Tuning (speed density).

    Sold: 1981 GMC LB RC 1500 2002 4.8L 4L60E 12 bolt 3.73 Richmond Lock Right AC PS Nelson Performance tuning

  10. #10
    It has been pretty windy this week with the cold front coming in.

    Now its starting to make a bit more sense. I just thought that was a huge drop out of no where.

    Thanks for the help

+ Reply to 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