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Mpg keeps getting worse.

Discussion in 'Gen 3 Prius Fuel Economy' started by kyle7, Jan 1, 2016.

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  1. kyle7

    kyle7 New Member

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    I bought my 2014 Prius in May of 2014. Now has 42k miles. I once remember getting over 50mpg, typically would get 45-47mpg. I take it in every 5k miles for its service and it comes back good according to them. The mpg has gotten worse and worse. I made a fishing trip and put about 700 miles on it in 3 days, averaged maybe 35 mpg. The current tank I'm on is less than 30mpg. Only thing the dealer said is that i can do an engine flush and it MIGHT help. And words of advice?
    This is a little frustrating since i bought the car for the same reason everyone else has but my mpg is much worse than what many others get.
     
    #1 kyle7, Jan 1, 2016
  2. frodoz737

    frodoz737 Top Wrench

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    At 42,000 miles would it be right to assume you have new tires now? Checked the pressures lately?
     
    #2 frodoz737, Jan 1, 2016
  3. CR94

    CR94 Senior Member

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    Any chance the weather has been cooler lately than it was when you were getting 45-47 mpg? Something must be different in conditions now, or you're driving faster?
     
    #3 CR94, Jan 1, 2016
  4. kyle7

    kyle7 New Member

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    Tires are a little lower than what most prius drivers have theirs at.
    It has been cold lately, but last winter the mpg wasn't this low and as it got into this last summer, my mpg didn't increase at all. Dropped into the winter and never went up. My driving i would say I've gotten more conservative with.
    If you think a both cold and lower pressure changes mpg by 15+ i think thats crazy, but I'll pump my tires up to 42/40 and see how my next tank goes.
     
    #4 kyle7, Jan 1, 2016
  5. bisco

    bisco cookie crumbler

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    welcome! at your mileage, there doesn't seem to be anything that would normally apply to higher mileage vehicles. nix on the 'engine flush' whatever that is. are the tyres original? how is alignment? any accidents? 12 volt health? what are your driving routes like? how is your oil level? air filter clean? 87 octane gas?
     
    #5 bisco, Jan 1, 2016
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  6. kyle7

    kyle7 New Member

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    Tires just got changed. Alignment got done with the tires. No accidents. Havent checked the battery, driving routes change due to place of next fishing trip. Oil just got changed. Air filter is clean. Only thing left would be gas according to your post, not sure of the octane level, but shouldn't make that much of a difference right? I'd love to get over 50mpg like other prius drivers.
     
    #6 kyle7, Jan 1, 2016
  7. JimN

    JimN Let the games begin!

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    Have you looked to see if you are dragging a brake?
     
    #7 JimN, Jan 2, 2016
    N.J.PRIUS and bisco like this.
  8. Mendel Leisk

    Mendel Leisk Senior Member

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    What are your new tires?
     
    #8 Mendel Leisk, Jan 2, 2016
  9. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Start with basics: Fuel economy complaints/queries? Please copy, paste & answer these questions, esp. if you're new | PriusChat

    When you are ready, the follow-up is to test the car to determine if there is something wrong with it.

    BTW, is that Washington State or DC?

    Thanks,
    Bob Wilson
     
    #9 bwilson4web, Jan 2, 2016
  10. Manhal K Alrashdan

    Manhal K Alrashdan Junior Member

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    Try this method :disconnect your 12v battery's negative terminal for about 10 minutes. This will reset the car's data and may improve your mpg rate.I know few who tried it and got good results.
     
    #10 Manhal K Alrashdan, Jan 2, 2016
  11. frodoz737

    frodoz737 Top Wrench

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    Tires, tire pressures seem to have the biggest effect on mpg for during normal operations assuming the wheels are stock. Most new tires will reduce mpg 3-10 mpg depending on your choice and time required to cut them in. Hot summer and cold winter temps can drop another 2-7 mpg.
     
    #11 frodoz737, Jan 2, 2016
  12. kenichols29

    kenichols29 Active Member

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    Try a fuel system treatment. My mpg dropped so I added one around 37,000 miles and I picked up a couple mpgs after that my mpgs went back up to where it was when I got the car.
     
    #12 kenichols29, Jan 3, 2016
  13. kyle7

    kyle7 New Member

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    I got the yokohama avid ascend

    Would this possibly help improve the 15+mpg I have lost since i got the car?

    So I've pumped up my tires and unplugged the battery to reset the car, ive managed to add 3-5mpg but im still under 35mpg according to my car. Havent drove a full tank to calculate it, but the computer is usually 1-2mpg over what i actually get and im at 34mpg right now.
     
    #13 kyle7, Jan 7, 2016
    Last edited by a moderator: Jan 8, 2016
  14. Mendel Leisk

    Mendel Leisk Senior Member

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    What sort of driving, what speed? Really high speeds are tough on mpg.

    Right after a drive, feel all 4 wheels, see if any feel hot, could indicate a dragging brake.
     
    #14 Mendel Leisk, Jan 8, 2016
  15. xliderider

    xliderider Senior Member

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    Feel the brake rotors, not the wheels, carefully in case they're really hot. ;)
     
    #15 xliderider, Jan 8, 2016
  16. kenichols29

    kenichols29 Active Member

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    Are you calculating by hand or are you using the HSI display?
    Not that much but you might pick up 2 to 5.
     
    #16 kenichols29, Jan 8, 2016
  17. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Hey, I got the same thing yesterday:
    After helping my wife in the house and taking care of our dogs, I forgot to turn off the car. It ran all night and instead of +50 MPG for ~120 miles, it was down to 36 MPG for ~120 miles. It happens but the car was nice and toasty.

    Bob Wilson
     
    #17 bwilson4web, Jan 12, 2016
  18. bisco

    bisco cookie crumbler

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    i hear ya.:coffee:
     
    #18 bisco, Jan 12, 2016
  19. vday

    vday Member

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    Sounds to me like a hybrid battery problem
    Get the Battery checked
     
    #19 vday, Jan 13, 2016
  20. fopoku2k2

    fopoku2k2 Member

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    What does it mean to drag a break and how can it be fixed?

    SM-G925F ?
     
    #20 fopoku2k2, Apr 17, 2016
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