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Improve 70k prius mpg?

Discussion in 'Gen 3 Prius Fuel Economy' started by Darklandscape, Sep 13, 2022.

  1. Darklandscape

    Darklandscape Junior Member

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    I have a gen 3 prius with 70 k miles.
    It gets 37-39 mpg
    I drive quite smoothly and break early.

    I tested the battery and it looks to be between 70-80 percent. The car seems to roll just fine.

    I've changed the spark plugs with toyota oem spark plugs.
    Cleaned the maf sensor.
    Cleaned the throttle body.
    Replaced both air intake filter, and cabin filter.
    Put in a Brand new 12 volt battery and tested the voltage and confirmed it's good.
    Used multiple bottles of techron fuel system cleaner.
    Pumped the tires to 39 psi.

    What should I consider trying next considering the milage is still on the lower side for a prius.

    Is there any chance that the inverter fluid could be causing this drop in mpg?
     
  2. bisco

    bisco cookie crumbler

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    when you say 'brake early', i hope you mean 'release gas pedal'

    what tyres are you running? are they LRR?

    when you say 'drop in mpg', what did you used to get?

    have you owned since new? or how long years/miles?

    no, inverter fluid is fine.

    has your commute changed in any way? seasonal weather changed? hvac use? average speed/acceleration?

    jack up the car and check for free wheel spin, just in case
     
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  3. nicoj36

    nicoj36 Active Member

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    Try this reset and also give it a bottle of fuel treatment
     
  4. Mendel Leisk

    Mendel Leisk Senior Member

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    What kind of driving are you doing, what speeds?

    Level or hilly?

    No park-and-run-the-AC?

    You’re the main driver?

    What tires on it?
     
  5. Mendel Leisk

    Mendel Leisk Senior Member

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    Rear wheels mainly, hard to judge front. And yeah: any recent brake work?
     
  6. Darklandscape

    Darklandscape Junior Member

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    I just put in Michelin defenders, no change in mpg, but once they break in maybe there will be some improvement.

    Yes I mean release gas pedal early.

    By drop in mpg I mean I just get lower mpg than the average gen 3 prius.

    I am not the original owner.
    I have bought it recently.

    Should I check both front and back wheels for free spin?
     
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  7. Darklandscape

    Darklandscape Junior Member

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    Which brand of fuel treatment would your recommend?
     
  8. Mendel Leisk

    Mendel Leisk Senior Member

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    Just rear. See “rear brake drag” in my signature. If on phone turn it landscape to see signatures.
     
  9. fuzzy1

    fuzzy1 Senior Member

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  10. nicoj36

    nicoj36 Active Member

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  11. Darklandscape

    Darklandscape Junior Member

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    70% city and 30% highway
    Mostly level with some hills occasionally.

    I am the only driver.

    I run the ac at low and 3 bars for the fan. Sometimes park and run, in my testing with none stop driving there wasn't a substantial difference between the two.

    Just got some Michelin defenders on them. I had an allignment on my previous set of wheels, but thinking I should get an allignment again because the car seems to be pulling to the right.
     
    #11 Darklandscape, Sep 13, 2022
    Last edited: Sep 13, 2022
    Mendel Leisk and bisco like this.
  12. Darklandscape

    Darklandscape Junior Member

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  13. Darklandscape

    Darklandscape Junior Member

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    Should I get an allignment before reseting the steering angle? Car seems to pull a bit to the right.
     
  14. fuzzy1

    fuzzy1 Senior Member

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    As in "LO"? If so, when using AC, a bit of fuel can be saved by cranking the set temperature up to something higher, but still sufficiently comfortable. And if lacking passengers, aim the near passenger bent towards yourself, close the far passenger vent.
    My Michelin Defenders were not low rolling resistance, but were otherwise better tires than the OEM factory tires.

    Did the previous tires show wear pattern signs of misalignment?
     
  15. Darklandscape

    Darklandscape Junior Member

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  16. Darklandscape

    Darklandscape Junior Member

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  17. rjparker

    rjparker Tu Humilde Sirviente

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    An old hybrid battery will cost you 4-5 mpg as will sitting in Park while keeping it in Ready. Understanding that driving habits matter helps because you want to maximize regen. That means letting up on the gas when going down any grade or hill. Anticipating a stop a block away and gently applying the brakes to stay in regen. No fast acceleration and staying at or below 60 mph instead of 70 or 75. Ac is important for the battery cooling but costs you gas. To maximize mpg keep it at 78 when you can. Inflate tires a few pounds more than the door sticker. Check for wheel bearing and brake drag.
     
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  18. Darklandscape

    Darklandscape Junior Member

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    Sadly I don't remember exactly what the wear pattern was like, I know they were pretty worn down. When I got the allignment I was told that the car was already in relatively good allignent. I may have the paper with all the allignment details. Do you want me to try to find it?

    BTW should I only go to a toyota place for a allignment or will any reputable allignment place work?
     
  19. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Air conditioning impacts mileage significantly. Use less if you can, be smart about using it- leave it set to auto so it can save you fuel when possible. Use a sunshade on the windshield every single stop. Consider a dark tint for the other windows if local laws allow.

    On the highway, sticking closer to 55mph yields enormous savings. 70+ is where every car is going to burn a lot of gas, Prius can't help as much. There may be different routes you could take for common trips that let you keep the speed down.
     
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  20. Grit

    Grit Senior Member

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    Bill norton says gimme actual data or else it’s all speculation!