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2015 Prius Trim 2 subpar MPG

Discussion in 'Gen 3 Prius Fuel Economy' started by plai7778, Jan 4, 2017.

  1. plai7778

    plai7778 Junior Member

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    Just bought a usedCPO 2015 Prius trim2 w 10k miles on it. I got a phenomenal deal on it. However I noticed that it's fuel economy is subpar. Since I got the car in 25-55 degree Cali winter weather I've been driving like a grandma in the city and only got 47 on the hsi. I never go past the power bar always on econ mode. I've goodyear assurance fuelmax tires that are at 42psi front and 40 psi back. I recently took a 250mi road trip, I went around 74-78mph I used cruise control the whole way and it was middle of the night, drove w a mpg conscious and got 40mpg on the hsi. I'm starting to worry I bought a lemon. With the way I've been driving I expect about 50 city and 45 highway. Any thoughts?

    Posted via the PriusChat mobile app.
     
  2. Phatlife

    Phatlife Member

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    I'm getting very good milage with my 2015 persona model. sometimes it can be the tires, altitude and if your a lead foot. let the car calculate the mpg.. colder temps will require a decent warm up for a few min. I'm getting anywhere from 45 to 57 mpg mixed in nj winter temps and summer with full ac running I'm getting close to 55 plus mpg mixed city and Highway. it also could be bad fuel.. I had bad fuel from Costco, car was very hesitant ans sluggish.. try changing fuel.. use 0-20w oil mobile 1 green cap and mobil 1 premium filter. let us know after a different fuel fill up.

    SM-G935T ?
     
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  3. plai7778

    plai7778 Junior Member

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    The car is used but CPO. Tires are good. Air filter is good Been driving like an old person so no lead foot. Only thing I can think of is the cold weather or my 12v battery. Anything else that I'm missing? I should really be getting 50s in the city and mid 40s on the highway. It's been about 300 miles
     
  4. Phatlife

    Phatlife Member

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    I'd swap.put the fluids, dealers use that cheap oil synthetic blend crap. I only use mobil1 the one made for Honda and Toyota hybrid cars. 20161127_032352.jpg 20160917_092525.jpg 20161206_191209.jpg

    SM-G935T ?
     
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  5. Phatlife

    Phatlife Member

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    that was Dec 6th I drove the car last.. mixed city and Highway driving about 70mph give or take with NJ traffic , Temps are 30s

    SM-G935T ?
     
  6. Phatlife

    Phatlife Member

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    mobil1 oil filter.. I picked up a bunch on amazon for 9 bucks.. normally 20 bucks.. here is a few pics of my milage, a little has dropped once I changed out the oem toyo proxes.. but can't complain with current tires.. FYI I'm running 17s. 20161104_175124.jpg 20161128_024749.jpg 20161104_175124.jpg 20161016_163234.jpg

    try new fluids, filters, and try a different gas station.. plus you need to break the car in for at least 2k miles to see a difference in mpg as well.. good luck and keep us updated. I've posted pics for my daily commute.. :)

    SM-G935T ?
     
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  7. Phatlife

    Phatlife Member

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    sorry for the sideways posting, that Tapatalk app..

    SM-G935T ?
     
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  8. Kramah313

    Kramah313 Active Member

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    The first tank I had of my CPO 2012 last year was about like that, high 40s on HSI. As an experiment, I tried not driving so carefully and switched to power mode. I drive pretty conservatively anyways, so it's not like I was going to hot rod it. My MPG went up by about 5. I was spending my time accelerating slowly, which is less efficient than quicker stronger bursts. So now I use power mode almost all the time (really because it matches the pedal feel of our other car) but it has never been that low again. Maybe try not granny driving it for a tank just to make sure it's not something with driving technique. Also, depending on how long you've had it some say the ECU goes through a learning curve and improves MPG over time.
     
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  9. Phatlife

    Phatlife Member

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    I only use power mode to merge in heavy traffic, I just drive in normal, never in economic mode, too spongy.. acceleration is not bad.. could be better.. but for what I use it for its fantastic. if I want a faster car, then the mpg will hurt.. power mode will only last till the battery drains out, then you back on the engine..

    SM-G935T ?
     
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  10. plai7778

    plai7778 Junior Member

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    Wow thanks I'll def give that a go. Maybe I am milking the petal too much
    At worse I've a CPO on it
     
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  11. plai7778

    plai7778 Junior Member

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    Yeah I've been wanting to put Mobil 1 on it. Maybe I'll do it sooner than the first 5k miles I put on it
     
  12. Phatlife

    Phatlife Member

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    I change mine every 10k.. or if the car feels sluggish, I don't burn any oil ans still comes out brownish yellow not black..

    SM-G935T ?
     
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  13. Phatlife

    Phatlife Member

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    make sure it the hybrid formula , the one with green cap. any other will have sluggish performance.

    SM-G935T ?
     
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  14. ALS

    ALS Active Member

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    Lots of issues that can affect your fuel mileage in a Prius.

    1. Are you driving with the A/C and or the Heater on?
    Both will affect your fuel mileage in a negative way.

    2. What tire pressure are you running, above 40 psi, or factory recommended pressures?

    3. Speed kills mileage

    4. All gasoline is not the same.
    My 1997 Volvo 960 was getting around 26.5 mpg at 65 mph.
    Always ran the cheapest premium I could score.
    Added a bottle of Techron and two to three tanks of Shell V Power with Nitro
    the car is now back up to 29.2 mpg at 65 mph.

    Switched my Prius back to Shell exclusively, after a bottle of Techon and a few tanks
    I saw my highway mileage increase by about 1.5-2.0 mpg

    Yes there is a difference between El-Cheap-O gas and a top tier gasoline.

    Check your wheels and make sure you don't have a sticking brake caliper or parking brake.

    I don't know why people have an issue with Toyota's 0W20 oil. It is a very good oil right up there with any of the top brands synthetics.

    I do bi-annual oil changes with factory 0W20 and have had ZERO oil issues with 64K miles.
     
    #14 ALS, Jan 5, 2017
    Last edited: Jan 5, 2017
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  15. plai7778

    plai7778 Junior Member

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    If I have a sticking brake calipers or parking brake, would any lights show up?
    I didnt have the heat or ac on was consistently going 75-77mph w cruise for 250 miles between 3am-6am and got 42mpg on hsi 39.5 real mpg. Tires 42/40. I feel like I should get this mpg if I was pushing 80. Mostly what I read people are reporting 44mpg at my speeds.

    Posted via the PriusChat mobile app.
     
  16. ALS

    ALS Active Member

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    Well if you slowed down to 65 mph your fuel mileage would be in the fifty two to fifty four miles per gallon area.
     
  17. plai7778

    plai7778 Junior Member

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    At 65mph flat road at 53 degree F w cruise, my hsi says 47.8mpg after 20miles....Very far off from 52mpg

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  18. bisco

    bisco cookie crumbler

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    are you in cold country with reformulated gas? have you tested the 12v battery? a dragging caliper will not set off a dtc. you have to spin the whel or at least feel for heat after a long drive.
     
  19. RMB

    RMB Senior Member

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    Hi there, I am also in Cali, Bay Area to be exact. It is the colder weather that's causing the lower MPG, nothing really to worry about. See my below graph for my winter gas mileage in Dec and Jan., always down to 47mpg while my other months I can go over 50mpg calculated. Once we are into warmer months your mpgs will be higher.

    Untitled.jpg
     
  20. plai7778

    plai7778 Junior Member

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    On my drive between SF to LA I got 42mpg on the hsi driving in the middle of the night (3am around 40°F )going between 76-79mph. Real time mileage is 39.5mpg. Even in the city I'm driving very slow and mpg optimized, I can only get around 49mpg on hsi. Anything else I can check for?

    Posted via the PriusChat mobile app.