1. Attachments are working again! Check out this thread for more details and to report any other bugs.

Solved my bad MPG

Discussion in 'Gen 2 Prius Fuel Economy' started by JC91006, Nov 13, 2017.

Page 2 of 2
  1. audiodave

    audiodave Active Member

    Joined:
    Feb 3, 2017
    788
    269
    0
    Location:
    US
    Vehicle:
    2004 Prius
    Model:
    Five
    Cleaning the maf sensor and throttle body could change things too.

    Posted via the PriusChat mobile app.
     
    #21 audiodave, Jan 28, 2018
  2. JC91006

    JC91006 Senior Member

    Joined:
    Nov 10, 2013
    16,525
    8,428
    0
    Location:
    Los Angeles, CA
    Vehicle:
    2008 Prius
    Model:
    II
    My car's mpg is still not up to where my other gen2 cars are at, I'm going to swap the MAF sensor from my 50mpg gen2 and see if anything changes.
     
    #22 JC91006, Jan 28, 2018
    TheLastMojojomo, Prodigyplace, Mendel Leisk and 1 other person like this.
  3. Mendel Leisk

    Mendel Leisk EGR Fanatic

    Joined:
    Oct 17, 2010
    56,664
    39,220
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Are they the same physically? Interesting. Hopefully same internally as well.
     
    #23 Mendel Leisk, Jan 28, 2018
  4. JC91006

    JC91006 Senior Member

    Joined:
    Nov 10, 2013
    16,525
    8,428
    0
    Location:
    Los Angeles, CA
    Vehicle:
    2008 Prius
    Model:
    II
    Both are identical, 2005 package 2.

    The lower mileage one is the one with the lower mpg. Only 113000 miles. The one with 190000 gets 50mpg
     
    #24 JC91006, Jan 28, 2018
    Mendel Leisk likes this.
  5. JC91006

    JC91006 Senior Member

    Joined:
    Nov 10, 2013
    16,525
    8,428
    0
    Location:
    Los Angeles, CA
    Vehicle:
    2008 Prius
    Model:
    II
    Swapped the MAF sensors today. Initial test drives were very positive, low 50mpg on both cars. Now this is strange....

    I'll drive them for a week and see what happens after a few hundred miles.
     
    #25 JC91006, Jan 29, 2018
    Mendel Leisk likes this.
  6. audiodave

    audiodave Active Member

    Joined:
    Feb 3, 2017
    788
    269
    0
    Location:
    US
    Vehicle:
    2004 Prius
    Model:
    Five
    I changed mine and it didn't help. Got the best mileage with a dirty air filter, dirty t body and old sensor. Lol
    235,000 miles.

    Posted via the PriusChat mobile app.
     
    #26 audiodave, Jan 29, 2018
  7. audiodave

    audiodave Active Member

    Joined:
    Feb 3, 2017
    788
    269
    0
    Location:
    US
    Vehicle:
    2004 Prius
    Model:
    Five
    I suspect if you had reset the computer it just needs time to settle to low 40's mpg again.
    I'm ready to change my injectors and O2 sensor. Low 40's is alI get.

    Posted via the PriusChat mobile app.
     
    #27 audiodave, Jan 29, 2018
    Prodigyplace likes this.
  8. audiodave

    audiodave Active Member

    Joined:
    Feb 3, 2017
    788
    269
    0
    Location:
    US
    Vehicle:
    2004 Prius
    Model:
    Five
    Maybe that upstream o2 sensor is a little off. Thinking of changing mine. I'm sure it's efficiency is off after 236,000 miles.

    Posted via the PriusChat mobile app.
     
    #28 audiodave, Feb 10, 2018
    SFO likes this.
  9. milestoempty

    milestoempty Junior Member

    Joined:
    Nov 30, 2008
    21
    3
    0
    Location:
    Annapolis
    Vehicle:
    2008 Prius
    Watching this...

    Just replaced the 12v battery in my car 2 months ago. Two weeks ago I did an oil change, air filter, and cleaned the MAF (111k) and now Im averaging 43k miles down from 49. Replaced my plugs about 20k miles ago.
     
    #29 milestoempty, Feb 12, 2018
  10. JC91006

    JC91006 Senior Member

    Joined:
    Nov 10, 2013
    16,525
    8,428
    0
    Location:
    Los Angeles, CA
    Vehicle:
    2008 Prius
    Model:
    II
    How's your tires and alignment?
     
    #30 JC91006, Feb 12, 2018
    Raytheeagle likes this.
  11. audiodave

    audiodave Active Member

    Joined:
    Feb 3, 2017
    788
    269
    0
    Location:
    US
    Vehicle:
    2004 Prius
    Model:
    Five
    How many tanks of gas have you ran through? Assuming computer was reset.

    Posted via the PriusChat mobile app.
     
    #31 audiodave, Feb 13, 2018
  12. audiodave

    audiodave Active Member

    Joined:
    Feb 3, 2017
    788
    269
    0
    Location:
    US
    Vehicle:
    2004 Prius
    Model:
    Five
    #32 audiodave, Mar 4, 2018
  13. Suzan OBrien

    Suzan OBrien New Member

    Joined:
    Mar 25, 2018
    2
    0
    0
    Location:
    Fresno CA
    Vehicle:
    2006 Prius
    Model:
    N/A
    I was having horrible MPG... and still do. About a year ago I put in Platinum plugs hoping that would help, but it' didn't. I am getting 40 at 144K and good maintenance.
     
    #33 Suzan OBrien, Mar 25, 2018
  14. Mavi

    Mavi Active Member

    Joined:
    Oct 12, 2015
    484
    285
    0
    Location:
    San Diego,ca
    Vehicle:
    2020 Prius Prime
    Model:
    XLE
    Any update? My prius is now down to 39mpg, while my brothers gets 44 same conditions throughout. So trying to figure out why. Also noticing some knock.
    Using the SK16R11
     
    #34 Mavi, Mar 25, 2018
  15. JC91006

    JC91006 Senior Member

    Joined:
    Nov 10, 2013
    16,525
    8,428
    0
    Location:
    Los Angeles, CA
    Vehicle:
    2008 Prius
    Model:
    II
    I find most of my local driving is still on the lower mpg side. I attribute that to the 17" tires. On the highway, I avg close to 47mpg.

    I'm not sure if the spark plugs change did anything as local driving mpg is still around 41 mpg
     
    #35 JC91006, Mar 25, 2018
  16. audiodave

    audiodave Active Member

    Joined:
    Feb 3, 2017
    788
    269
    0
    Location:
    US
    Vehicle:
    2004 Prius
    Model:
    Five
    Same with me, higher mileage on the highway than around town. Low 40's to high 40's on the highway. 237,000 miles on 15 inch wheels.

    Posted via the PriusChat mobile app.
     
    #36 audiodave, Mar 25, 2018
  17. JC91006

    JC91006 Senior Member

    Joined:
    Nov 10, 2013
    16,525
    8,428
    0
    Location:
    Los Angeles, CA
    Vehicle:
    2008 Prius
    Model:
    II
    On my other cars with 15" tires I avg over 45mpg no matter if I drive local or highway
     
    #37 JC91006, Mar 25, 2018
  18. audiodave

    audiodave Active Member

    Joined:
    Feb 3, 2017
    788
    269
    0
    Location:
    US
    Vehicle:
    2004 Prius
    Model:
    Five
    Well most of my around town driving is short trips and cold starts. So the worst of milage.

    Posted via the PriusChat mobile app.
     
    #38 audiodave, Mar 25, 2018
  19. Erik Owens

    Erik Owens Member

    Joined:
    Mar 25, 2018
    162
    59
    0
    Location:
    Florida
    Vehicle:
    2010 Prius
    Model:
    Three
    I know it is always wisest to check the engine components to fix issues with MPG but being a hybrid I would always check to see if they HV battery is doing well also. MPG can suffer on the engine side and also the HV Battery side mainly where the battery cell connections are bolted together. They can be corroded and/ or the battery can be slowly starting to discharge intermittently.
    Not to say that your main issue being your plugs but as always keep it in the back of your mind. 2005 model. Possibly past 100K like I have read. Plus Iridium shouldnt need to be gapped but plugs do depend on resistance and type of course.
     
    #39 Erik Owens, Mar 25, 2018
    audiodave likes this.
  20. audiodave

    audiodave Active Member

    Joined:
    Feb 3, 2017
    788
    269
    0
    Location:
    US
    Vehicle:
    2004 Prius
    Model:
    Five
    Curious on the plugs, gap was not correct on mine. They needed to be gapped. 43 is a number not every gapper has.

    Posted via the PriusChat mobile app.
     
    #40 audiodave, Mar 25, 2018
(You must log in or sign up to post here.)
Page 2 of 2