Gas mileage decline since hitting curb

Discussion in 'Gen III 2010+ Prius Technical Discussion' started by rtlt, Jul 29, 2011.

  1. rtlt

    rtlt New Member

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    During May our car hit a curb hard enough that both tires on the drivers side had to be replaced ( flat and a bubble). At the time, the technician tested the car for other damage and found none---- other than needing to be realigned - which he did. Since then, the gas mileage has declined and seems to be getting worse.
    Prior to the incident, we had been averaging about 53 mpg with better mileage in good weather and a little less in the heat of the summer. After the incident, the mileage seemed to drop to about 47-48 . Then in June the car was due for 20,000 mile service which was done and no problems found. Oil was changed and airfilters checked ( they had been replaced at 15,000 miles). Since the service, the mileage hasn't improved and seems to be getting a bit worse --last couple tanks down to about 45.5mpg. There has been no change to car weight, driver style, or avg driving profile. I've tried a couple different brands of gasoline, checked air pressure, fluid levels etc.. I've been running the air conditioner in the summer but last year I was getting at least 50-52mpg during the summer. It feels that the car is struggling more in lower gears and not up-shifting as easy. Is there a sensor that maybe got out of line or some other part that could be causing this issue that is not quickly noticable when the car is on the rack ????
     
  2. billnchristy

    billnchristy Active Member

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    I'm thinking alignment still off?
     
  3. cyclopathic

    cyclopathic Senior Member

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    +1

    Perhaps he did not aligned it to OEM specs
     
  4. Dark_matter_doesn't

    Dark_matter_doesn't Prius Tinkerer

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    Given the amount of dissatisfaction with dealer service expressed in this forum, you should go to a private alignment shop for a suspension/alignment inspection. Are there ANY driving issues, like the car pulls to one side instead of tracking straight or pulls to one side upon hard braking? Does it tend to change direction when you hit a bump or go over a railroad crossing?
     
  5. rtlt

    rtlt New Member

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    No noticable alignment issues when driving. Wear on tires seem normal and there is no pulling of the car to either side of the road --seems to track straight. Haven't noticed any change when crossing railroad tracks but I wasn't focusing on that -- I will in future.
     
  6. dustoff003

    dustoff003 Blizzard Brigade #003

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    The Pruis does not have a automatic transmission with gears like most other autos have. It has a Continuously Variable Transmission (CVT).

    [ame=http://en.wikipedia.org/wiki/Continuously_variable_transmission]Continuously variable transmission - Wikipedia, the free encyclopedia[/ame]


    If you feel it acting like an automatic transmission shifting gears that could indicate damage to the driveline mainly the transaxle assembly.

    I would also advocate that you have the alignment checked elsewhere and ensure that the rear wheel alignment is checked and within specifications also.
     
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  7. kithmo

    kithmo Couch Potato

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    +1
    A 4 wheel alignment check.
    If the dealer only did a front wheel check then the car could be crabbing down the road.
     
  8. FLteacher

    FLteacher New Member

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    I wonder if it's the new tires. Were the tires replaced with the same exact type? Often there is a break in period for new tires as well.
     
  9. TheSpoils

    TheSpoils Member

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    This may sound silly, and some folks may disagree with me but... go check your oil. If it is at the full line or above, that is your answer.
    good luck
     
  10. ryogajyc

    ryogajyc Active Member

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    Generally in the US, this summer has been hotter than last, so perhaps the battery is hotter so the HSD is using less battery and more ICE power which would be consistent with your symptoms. Also, the A/C would be running harder than last year and a combination of the two would result in lower mileage this summer. Hitting the curb could be entirely unrelated.
     
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  11. sipnfuel

    sipnfuel New Member

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    Try rotating new tires to the front and old tires to the back.
     
  12. ryogajyc

    ryogajyc Active Member

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    That's not possible; both tires on the driver's side were replaced.
     
  13. sipnfuel

    sipnfuel New Member

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    Yes, so both tires on the left are new, and both on the right are old.

    Rotate the back left tire to the front right. Rotate the front right tire to the back left.

    Use jack stands, blocks and/or the spare tire if necessary to stand in.
     
  14. ursle

    ursle Gas miser

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    Cycle your emergency brake on and off a few times, raise the rear wheels and see if the rear brakes are adjusted to tight, clean your cabin air filter, is it time for a new 12v battery? Check your oil level, 2/3rd's up the dip stick, check the engine air filter, is it dirty?
     
  15. ryogajyc

    ryogajyc Active Member

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    Sorry, I misread your earlier post as swap front and back tires.

    If the tires aren't directional.
     
  16. revhigh

    revhigh MPG Enthusiast

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    I've found that my mileage has dropped roughly 4-5 MPG this summer. I was hoping for a gain, but that hasn't happened. It HAS been EXTREMELY HOT and the A/C has been in use constantly, which is what I attribute the MPG loss to. I had averaged around 48.9 MPG for the first 11K miles since January, when it was extremely cold. Ironically, I got better mileage on a brand new engine in the middle of the winter than I'm getting this summer. I'm sure that when the worst of the summer is over and I can stop using the AC so heavily that it'll go back to slightly over 50 again. My summer heavy AC mileage has been around 45, which really ticks me off, but it's been so hot that I don't care ... I HAVE to have the AC on, set at about 74. Even at 74 it runs full bore almost constantly due to the incredible heat we've been experiencing.

    REV
     
  17. Caug1

    Caug1 Member

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    What type of oil did dealer put in? wrong ,may be.
     
  18. F8L

    F8L Protecting Habitat & AG Lands

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    You've seen the video I posted that shows the 10mpg drop when the A/C compressor is running hard. It's no surprise that your mpg has dropped so much. The heatwave that your guys are experiencing leaves your no choice but to run. The A/C hard. Better to stay cool than suffer from heat exhaustion. :)
     
  19. 32kcolors

    32kcolors Senior Member

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    Were they replaced with equivalent LRR tires or just any tires that'll drop your mileage like a rock?
     
  20. Mendel Leisk

    Mendel Leisk Senior Member

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    +1 on the above.