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Unusual huge swing in fuel economy

Discussion in 'Gen 2 Prius Fuel Economy' started by hybridmel, Dec 17, 2009.

  1. hybridmel

    hybridmel Junior Member

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    Okay, so I expected that when cold weather hit that my fuel mileage would drop.

    However, imagine my surprise and shock, when it decreases by 75%!

    Normally, I fill up every 4-6 weeks, just depending on how much I drive. Well, the last 2 weeks, it is taking about a week to go through a whole tank. And, I am not driving hardly at all. I did not do a reset to see how many miles per tank. And, I am not keeping an eye on the actual mpg's. All I know is a tank is only lasting me a week.

    That seems like an awfully big drop, unusual I'd say.

    The guy at the dealership where I get it serviced said I needed to pump my gas more slowly, because it thinks there is more gas in there than there really is. But, I checked my receipts, and I am putting in pretty much the same number of gallons of gas as I always have before. So, I don't see how that could be true.

    Any ideas?
     
    #1 hybridmel, Dec 17, 2009
  2. F8L

    F8L Protecting Habitat & AG Lands

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    Without specifics on miles and number of gallons pumped I don't think anyone can really help you. Maybe you've been driving in B mode on accident?
     
    #2 F8L, Dec 18, 2009
  3. sfvb

    sfvb New Member

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    75%? I hope that's an exaggeration. The following are examples of a 75% decrease:

    was getting 40, now getting 10
    was getting 50, now getting 12.5
    was getting 60, now getting 15
    was getting 70, now getting 17.5
     
    #3 sfvb, Dec 18, 2009
  4. hybridmel

    hybridmel Junior Member

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    Well.......normally it takes at least 4 weeks to go through a tank of gas. Now, it is taking one week. To me, that is 75%.

    No difference in driving patterns or anything like that. Is my math off?
     
    #4 hybridmel, Dec 18, 2009
  5. F8L

    F8L Protecting Habitat & AG Lands

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    There is no math involved yet. We need more numbers. In one week you could have driven 200 more miles than the previous or maybe you pumped 2 gallons less.

    Please go fill up the fuel tank and reset your trip meter and drive till you get to the last two bars on your fuel gauge. Refill the tank and record the gallons pumped and the # of miles driven on that tank then post back up.
     
    #5 F8L, Dec 18, 2009
  6. ksstathead

    ksstathead Active Member

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    You should notice your instantaneous mpg being 10ish instead of 45-55ish with a 75% drop, and their should be a sputtering engine and smoke billowing all around perhaps.

    Edit your info to show the year of your Prius so we know what generation it is.
     
    #6 ksstathead, Dec 18, 2009
  7. Rokeby

    Rokeby Member

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    Perhaps the OP could shed some light on why his/her avatar says...

    "other non-hybrid," :confused:

    Is this even a Prius related matter?

    Even so, sounds like somebody with a handy-dandy siphon.

    Do you always lock your car... every single time?
     
    #7 Rokeby, Dec 18, 2009
  8. Codyroo

    Codyroo Senior Member

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    Start a log where you note your tank mileage and the amount of gas used to refill the tank (353 miles, 8.52 gallons for example). Track this over time. You, currently, aren't measuring fuel economy, instead you are measuring your fill-up interval.

    The two aren't interchangable.
     
    #8 Codyroo, Dec 19, 2009
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