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My MPG went down alot after 5k

Discussion in 'Gen 2 Prius Main Forum' started by dnoh, Aug 24, 2007.

  1. dnoh

    dnoh New Member

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    Ok, this is what happened. I used to drive 90 to 100 miles per day. Thank god, I don't have to do that again since I got relocated. but anyway, my first 4k miles, I used to get around 47 to 50 MPG. It was 80 % on highway mileage. So I was extremely happy. And I heard people are getting better MPG after car breakin, so I was looking forward to get the better Mileage later. However, when it was getting very close to my first oil change, my MPG dropped to 42 MPG. My driving style never changed, although I do drive really fast. Now my mileage is close to 9k, I am still only getting 44 to 45 MPG. Yeah, I am still happy about it but why can't I get close to 50 MPG like I used to? And last couple of weeks, because I got relocated, I only drive little less than 10 miles per day and it's all local, but my MPG still stay at around 44 to 45. What should I do? Please help.
     
    #1 dnoh, Aug 24, 2007
  2. Rae Vynn

    Rae Vynn Artist In Residence

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    Have you checked the air in your tires lately?
    Tell us about the oil change... did you do it yourself?
    If you had a dealer/mechanic do it, what oil did they use? how much?
    Have you checked the dipstick?
    You've said that you are making only local, 10 mile trips now... that is the bulk of the reduction in MPG, I'm sure.
     
    #2 Rae Vynn, Aug 24, 2007
  3. jdenenberg

    jdenenberg EE Professor

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    <div class='quotetop'>QUOTE(dnoh @ Aug 24 2007, 01:24 PM) [snapback]501579[/snapback]</div>
    Stop complaining and be happy with 40 - 45 MPG. Your Prius isn't able to take full advantage of electric assist until the ICE and its catalytic is fully warmed up. This reduces your MPG to about 35 for the first five minutes and still has some effect for the second five minutes.

    JeffD
     
    #3 jdenenberg, Aug 24, 2007
  4. qbee42

    qbee42 My other car is a boat

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    <div class='quotetop'>QUOTE(dnoh @ Aug 24 2007, 01:24 PM) [snapback]501579[/snapback]</div>
    Ten miles per day means short trips, and short trips kill your mileage.

    Tom
     
    #4 qbee42, Aug 24, 2007
  5. dnoh

    dnoh New Member

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    <div class='quotetop'>QUOTE(Rae Vynn @ Aug 24 2007, 02:00 PM) [snapback]501610[/snapback]</div>
    I haven't checked my tire pressure, what is the ideal pressure lvl I should keep?
    I got my oil change done at the Jiffy Lube. I paid extra to put synthetic Mobil 1.
    I should check the dipstick tonight.

    Yes, I love my new commute. 10 miles per day. I think I only have to put gas in my car once a month, LOL.

    <div class='quotetop'>QUOTE(jdenenberg @ Aug 24 2007, 02:01 PM) [snapback]501611[/snapback]</div>
    Oh, don't get me wrong. I am not complaining. I am still getting 44 to 45 MPG, that's amazing. My previous car was Mini Cooper S, and this small car was only getting around 25 MPG. And that's highway mileage. As you can see, I do have heavy foot. If I change my driving style, I think I can definately getting more MPG from my Prius but that's too much work for me. I was just wondering why my MPG dropped suddenly. But 45 MPG is still amazing, I doubt there's any car out there can do the same with my driving style.
     
    #5 dnoh, Aug 24, 2007
  6. Rae Vynn

    Rae Vynn Artist In Residence

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    <div class='quotetop'>QUOTE(dnoh @ Aug 24 2007, 11:07 AM) [snapback]501613[/snapback]</div>
    At the very least, you should have the pressure that is listed on the inside of the driver's doorjam.
    A lot of people looking for better MPG will increase that a bit, but do not exceed the max listed on the tires.

    Jiffy Lube. They may have 1) changed your tire pressure, 2) overfilled your oil, 3) not actually used Mobil1, 4) neglected to change the oil filter, 5) used the cheapest possible filter (Fram).

    You are close to 9k? I'd suggest doing your own changes, or else finding a much better place to have your oil changed. You may benefit from reading the owner's manual, as well.
     
    #6 Rae Vynn, Aug 24, 2007
  7. subarutoo

    subarutoo New Member

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    If you are taking shorter drives, it takes less gas than before, I'm sure. What is the problem? It may be less per gallon, but your overall usage must be lower than before. What's to complain about? I would gladly trade my 45 mile commute for a 10 mile one, and wouldn't be whining about a few less mpgs.
     
    #7 subarutoo, Aug 24, 2007
  8. paprius4030

    paprius4030 My first Prius

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    Things to look for, as other people suggested, make sure oil is not overfilled, keep your tire pressure at 42front, 40 rear, also check the engine air filter, it seems to collect dirt pretty fast, i usually have to change mine every 15k but if your in a dusty enviroment maybe sooner.
     
    #8 paprius4030, Aug 24, 2007
  9. Prius 07

    Prius 07 Member

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    Sounds to me that the key change that is the cause in your MPG drop is your shorter trips to work after relocating. Since you only have <10 miles drive to work most of that is spent with your ICE not warmed up. In the first 5 minutes you're probably only getting 25 MPG ... you can do the math for the total trip.
     
    #9 Prius 07, Aug 24, 2007
  10. morpheusx

    morpheusx Professor Chaos

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    maybe its because it's hot and you are using alot more a/c
     
    #10 morpheusx, Aug 24, 2007
  11. JimN

    JimN Let the games begin!

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    <div class='quotetop'>QUOTE(dnoh @ Aug 24 2007, 01:24 PM) [snapback]501579[/snapback]</div>
    dnoh, using an EBH will boost the mpg of the 1st 5 minutes. Blocking your grill will help a bit with the 2nd bar. 10 miles per day in presumably stop & go traffic is going to kill the mpg so 44-45 sounds reasonable.

    On a personal level, you may be able to see a bigger improvement if you can keep the temp at 78-79F and reduce your speed a bit.
     
    #11 JimN, Aug 24, 2007
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