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MPG Drop off

Discussion in 'Gen 2 Prius Fuel Economy' started by gregorye70, Mar 28, 2016.

  1. gregorye70

    gregorye70 Junior Member

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    I have a 2008 Prius that has had a significant drop off in MPG recently. I've been driving the car, which now has 165k miles for just over 5 years and in that time I have put 120k miles on it. Over my ownership the car has averaged 46 to 47 mpg. Two weeks ago I noticed that I was only getting about 327 miles on a tank of gas. I've always gotten somewhere between 400 and 480 through pulse and glide hypermiling. The Consumption read out shows no change, it always showed an average mpg within the 45 to 55 mpg range. There are no significant changes in driving conditions, habits or car load I can point to.

    If the hybrid battery is already going, wouldn't I be more likely to see a gradual decline in mpg instead of an abrupt one? Watching the "Energy" read out there doesn't seem to be any noticable difference with the battery pack charging to green or sustaining charge.

    Any ideas in terms of what could be happening would be greatly appreciated,
    Thanks!
     
    #1 gregorye70, Mar 28, 2016
  2. bisco

    bisco cookie crumbler

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    agree^^^ until you see a calculated difference over a period of fill ups, we have no evidence that your mpg's have dropped.
     
    #2 bisco, Mar 28, 2016
  3. fuzzy1

    fuzzy1 Senior Member

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    I'll second this. Or third, by now.
     
    #3 fuzzy1, Mar 28, 2016
  4. gregorye70

    gregorye70 Junior Member

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    Thank you for your response. I will watch the next few fill ups, and calculate individual mpg per tank. No, I have encountered the differences in mpg coming out of a cold winter before but not this "winter".
     
    #4 gregorye70, Mar 28, 2016
  5. tlstarkey51

    tlstarkey51 Junior Member

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    My mileage has dropped from the mid 40's to the mid 30's. I've been calculating this for each tank. Last September I had new tires installed and alignment. No change. It's an 08 with 80000 miles. I always take it in for scheduled service. Any ideas?
     
    #5 tlstarkey51, Apr 10, 2016
  6. bisco

    bisco cookie crumbler

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    what tyres and tyres pressure?
     
    #6 bisco, Apr 10, 2016
  7. S Keith

    S Keith Senior Member

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    How has the consumption meter changed?
     
    #7 S Keith, Apr 10, 2016
  8. tlstarkey51

    tlstarkey51 Junior Member

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    Michelin defenders and psi is factory recommened

    The meter rarely matches the real mpg. Years ago it was a lot better.
     
    #8 tlstarkey51, Apr 10, 2016
  9. bisco

    bisco cookie crumbler

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    could be a lot of things, check your oil level, 12 volt battery, might need throttle body cleaning, etc.
     
    #9 bisco, Apr 10, 2016
  10. S Keith

    S Keith Senior Member

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    That doesn't answer the question. The Prius has a fuel bladder, which makes per-fill-up calculations inaccurate - discussed extensively here. If you're not seeing a similar drop in the consumption gauge, then it's probably not real.
     
    #10 S Keith, Apr 10, 2016
  11. aurelio

    aurelio Member

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    Check how much does it take to drop from 6 to 2 bars. When coasting on ev mode. I remember a thread that said that if it takes 2 minutes or less, the battery is going to fail sooner than later. I suggest to check for signs of a damaged battery to see were it takes you.

    Nexus 10 ?
     
    #11 aurelio, Apr 10, 2016
  12. S Keith

    S Keith Senior Member

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    ^^^ Don't do this. It's impossible to quantify.

    Conduct the discharge test linked in my signature.
     
    #12 S Keith, Apr 10, 2016
  13. stockdaddy

    stockdaddy Member

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    I use an app to monitor the fill-ups. I do notice it can vary from 40mpg to 50mpg but averages out to 46-47mpg.
     
    #13 stockdaddy, Apr 20, 2016
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