Car mpg lies

Discussion in 'Gen 4 Prius Fuel Economy' started by Buggs1a, Sep 13, 2025 at 10:36 PM.

  1. Buggs1a

    Buggs1a Junior Member

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    So ok. The car shows over 61 avg mpg for me. That’s a lie I just realized. Toyota should be punished for lying. We rely on that info. It says your ODO. Is that a lie too? How do we know? Mpg is lying. So why not odo too? It says how many miles I’ve gone on my trip meter. Is that lying too?

    right now im at half tank. I’ve gone 310 miles so far. Mpg shows 61.x. I forget the x. So this makes sense though. At half tank. 310 miles. But hmm.

    I’m confused. But I know the avg mpg isn’t accurate. I got over 60 mpg it always shows. But never 600 miles on my tank. At most 525 or so from full to right when the gas light came on. Then I went 15 miles or 20 to fill up. This was about 525 miles.

    I prefer to fill it when gas is at the last line before the min. That gets me 440 miles or so.

    I don’t have the mindset tho to manually figure this out. No biggy to be that accurate. Not manually. But dang it the car should not lie.
     
  2. RRxing

    RRxing Senior Member

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    Dang, wait until you find out why the speedometer reads high... :rolleyes:
     
  3. Mendel Leisk

    Mendel Leisk MMX GEN III

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    1. If it’s similar to gen 3, multiplying the displayed mpg by 0.93 should be close. (It’s 7% optimistic)

    2. speedometers tend to show slightly higher than true speed, a mostly vain attempt to get drivers to slow down.

    3. odometer will VERY likely be accurate, reasonably so.