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Astoundingly sudden high mileage yesterday

Discussion in 'Gen 2 Prius Fuel Economy' started by howardbc, Jan 26, 2011.

  1. howardbc

    howardbc Member

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    I have a 2008 and I usually only get 44-46 MPG but on a few rare occasions it will jump up so high it almost scares me. Yesterday I had the heat and fan on (but not high) and the next thing I know the MPG is almost 70 MPG! This has happened before. I had filled up the tank the day before but my MPG was not extraordinary afterward. Later yesterday, after parking for a few hours, it came back down to its usual 44-46 MPG. Is there a glitch? I was not driving anywhere different. It is just perplexing. Any thoughts? Thanks.
     
    #1 howardbc, Jan 26, 2011
  2. bisco

    bisco cookie crumbler

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    not sure what mean about mpg. i usually measure it by the tankful. i use the current reading for p&g etc., i never see that in one place. it goes from mid teens to 99.9 depending on what i'm doing. the average moves a bit on a new tank and less and less as i put more miles on it. what exactlyare you describing?
     
    #2 bisco, Jan 26, 2011
  3. howardbc

    howardbc Member

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    Thanks, bisco. I an getting my average MPG from the screen that shows one's average MPG. Not the screen that shows the immediate/current MPG. My Prius is a 2008 so the screen displays may be a little different from your 2005.
     
    #3 howardbc, Jan 26, 2011
  4. bisco

    bisco cookie crumbler

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    i also have an 08. i filled up yesterday and the average started in the upper 70's. then after 10 miles or so, it was in the low forties. by the time i got home, it was 53. it will probably hover in the low 50's for the tank, unless the weather changes drastically or i take some longer trips than my regular commute.:)
     
    #4 bisco, Jan 26, 2011
  5. uart

    uart Senior Member

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    Hi howardbc, the one important thing that you didn't tell us was how many miles you had traveled since filling up when this happened.

    I'm assuming that you reset MPG data when you filled up the tank (can you clarify this point). When you calculate the average MPG over just a few miles then of course you can get a lot of variation as a result (much like you do with the 5 minute averages).

    For example I live on a hill so there are several destinations where I can travel around 10km and average only 2.5L/100k (94 MPG). So if I were to fill up here and then immediately drive one of these routes then my "average" MPG would be ridiculously high. Of course when I return it's more uphill so I only average 6.5L/100k (35 MPG) on the way home giving an overall average of about 4.5L/100k (52MPG) which is close to my true average MPG over a full tank.
     
    #5 uart, Jan 27, 2011
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