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Suddenly Not Getting 50MPG

Discussion in 'Gen 2 Prius Fuel Economy' started by jburns7654, Sep 16, 2013.

  1. jburns7654

    jburns7654 New Member

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    Five
    I have had my 2007 Prius for about three months, and after the initial learning curve of how to drive a prius to get the maximum MPG I was averaging anywhere from 50 MPG to 55 depending on where I was driving. After a road trip from Milwaukee to Minneapolis the MPG went way down and I cannot seem to get it back up. On the road trip I had three other passengers and a light load of luggage so I understood when the Miles per Gallon was not as great, however since coming back home and unloading the extra people and luggage weight I have not gotten it to go back up. I drive the same route almost every day and I was always averaging 50 MPG, now I cannot get it to go past 45 MPG no matter how or where I drive. Also, I don't know if this makes a difference or not but on the way back from Minneapolis the triangle with the exclamation point turned on solid for the rest of the drive, after checking the manual took it in for an oil change which then turned off the alert sign. The light turning on made sense for the oil change as it had been 5,000 miles since the last one. Am I out of luck for getting the miles per gallon back up or is there something more wrong that I am not seeing?
     
    #1 jburns7654, Sep 16, 2013
  2. Eclipse1701d

    Eclipse1701d Prius Enthusiast

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    I am a little concerned. On an 07, the maintenance required soon light should come on to remind you of an oil change, not the red triangle with the explanation point. That denotes an error. Where did you have the service done?
     
    #2 Eclipse1701d, Sep 16, 2013
  3. jburns7654

    jburns7654 New Member

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    I took it to a local FF Tire for an oil change and tire rotation. Should I be worried about something else?
     
    #3 jburns7654, Sep 16, 2013
  4. Eclipse1701d

    Eclipse1701d Prius Enthusiast

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    Like I said, the red triangle denoted and error. This could be why your mileage dropped. Check your 12V battery to see what it holds a charge at after it sits all night and also, with the car on, remove the inverter fluid cap and check for turbulence. If you have a Prius aware scanner, check for any codes that may have been logged...
     
    #4 Eclipse1701d, Sep 16, 2013
  5. xpcman

    xpcman Senior Member

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    They probably dumped in 5 quarts of oil - over filling the Gen II Prius which should take approx 3 1/2 quarts. In a Prius overfilling will affect your MPG in this manner. They may also have used the wrong viscosity oil which would also affect MPG.

    Now the light probably came on to warn you of low oil level and you should learn how to check the dip stick as this may be a continual problem that you will need to monitor. You should never run a car hundreds of miles with the check engine light on! It needs to be checked immediately!
     
    #5 xpcman, Sep 16, 2013
  6. jburns7654

    jburns7654 New Member

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    Total doof moment I just realized that it was not the triangle but instead the maintenance required light which was then turned off by the guy doing the oil change. Sorry for the confusion.
     
    #6 jburns7654, Sep 16, 2013
  7. xpcman

    xpcman Senior Member

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    If the 12 Volt battery has not been replaced it should be done as soon as possible. It can fail to start with no warning and a 2007 Prius with the original battery is past due for a replacement. Note that your local shop does not carry the battery as it's specific the the Prius. So it might need to be special ordered. Good news is that you now have multiple options for replacement.
     
    #7 xpcman, Sep 16, 2013
  8. jburns7654

    jburns7654 New Member

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    So being that it was simply the maintenance required light and not something more drastic does it have anything to do with the drop in MPGs?


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    #8 jburns7654, Sep 17, 2013
  9. uart

    uart Senior Member

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    Probably not. Just watch it over the next few tanks full of fuel and see if it returns to normal.
     
    #9 uart, Sep 17, 2013
  10. Eclipse1701d

    Eclipse1701d Prius Enthusiast

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    I took a road trip to Miami a few years ago in my '07. Must have gotten some bad gas... My mileage sucked until I filled up the second time after returning. Then, everything went back to normal... However, things like a dirty throttle body, old spark plugs, etc. will lower mileage. Someone posted above that if they over filled your oil, it will lower your mileage. That is correct. The Prius is very sensitive to over fill.
     
    #10 Eclipse1701d, Sep 17, 2013
  11. vskid3

    vskid3 Active Member

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    The maintenance light comes on 5k miles after it was last reset. It doesn't mean that anything is wrong, just that 5k miles have passed (hopefully it was reset the last time the oil was changed, so you know when to change the oil next).
    I agree with xpcman, check the oil dipstick to make sure they didn't overfill it.
     
    #11 vskid3, Sep 22, 2013
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