Prius engine slightly stumbles..

Discussion in 'Gen 3 Prius Main Forum' started by Rob Stone, Feb 11, 2019.

  1. Rob Stone

    Rob Stone Junior Member

    Joined:
    Mar 7, 2008
    49
    15
    0
    Location:
    Portsmouth Ohio
    Vehicle:
    2015 Prius
    Model:
    ----USA----
    My 2015 Prius recently started a strange thing. When I let off the gas pedal to coast, the engine stumbles slightly and I feel it. When I gently press the gas, the engine slightly stumbles and starts. I can also press the gas pedal barely and hit a point where the engine stumbles slightly as long as I’m barely pressing the gas pedal.

    Another issue I noticed is when I accelerate hard on slick pavement, the traction light comes on but system is not retarding engine. I can spin the tires for a good distance...... any ideas as to how to troubleshoot this issue?
     
  2. JC91006

    JC91006 Senior Member

    Joined:
    Nov 10, 2013
    13,472
    6,036
    0
    Location:
    Los Angeles, CA
    Vehicle:
    2005 Prius
    Model:
    II
    Sounds like the EGR circuit/Intake ports should be cleaned. Too much carbon buildup. probably good idea to change spark plugs if you have high miles

    On your Avatar photo, what on earth are you doing there under the car?
     
    mjoo and Rob Stone like this.
  3. Mendel Leisk

    Mendel Leisk Sidewalk Supervisor

    Joined:
    Oct 17, 2010
    32,141
    21,107
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    How many miles?
     
  4. Grit

    Grit Senior Member

    Joined:
    Aug 22, 2017
    1,617
    1,433
    1
    Location:
    BOY
    Vehicle:
    2012 Prius
    Model:
    Four
    Traction light comes on because your tires are spinning while car is stationary thus traction control kicks in to stop the tires from spinning, feels like a horrible knock also. The way to troubleshoot is replace current tires with more grip.
     
  5. Rob Stone

    Rob Stone Junior Member

    Joined:
    Mar 7, 2008
    49
    15
    0
    Location:
    Portsmouth Ohio
    Vehicle:
    2015 Prius
    Model:
    ----USA----
    That’s not what’s happening. Engine is not being controlled at all during tire spin. When it works right, the engine stalls to allow tires to gain traction.
     
  6. Rob Stone

    Rob Stone Junior Member

    Joined:
    Mar 7, 2008
    49
    15
    0
    Location:
    Portsmouth Ohio
    Vehicle:
    2015 Prius
    Model:
    ----USA----
    189,000
     
    Mendel Leisk likes this.
  7. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    77,131
    32,446
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    start of a head gasket fail?
     
  8. Rob Stone

    Rob Stone Junior Member

    Joined:
    Mar 7, 2008
    49
    15
    0
    Location:
    Portsmouth Ohio
    Vehicle:
    2015 Prius
    Model:
    ----USA----
    That’s my son in my Avatar. Trying to remember what we were doing that day. That was our 2004 Prius.
     
    Raytheeagle and Mendel Leisk like this.
  9. Rob Stone

    Rob Stone Junior Member

    Joined:
    Mar 7, 2008
    49
    15
    0
    Location:
    Portsmouth Ohio
    Vehicle:
    2015 Prius
    Model:
    ----USA----
    Hope not!
     
  10. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    77,131
    32,446
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    me too!:)
     
    amos and Rob Stone like this.
  11. Rob Stone

    Rob Stone Junior Member

    Joined:
    Mar 7, 2008
    49
    15
    0
    Location:
    Portsmouth Ohio
    Vehicle:
    2015 Prius
    Model:
    ----USA----
    Seems like we had to remove wheel well for something. I know we removed nose of that car to replaced headlights once....now I am going to wonder about that the rest of the evening. Lol
     
  12. JC91006

    JC91006 Senior Member

    Joined:
    Nov 10, 2013
    13,472
    6,036
    0
    Location:
    Los Angeles, CA
    Vehicle:
    2005 Prius
    Model:
    II
    Looks like he's turning some tool, but that area, I don't know what's there.

    But I was thinking it looks a bit dangerous to be under there using a scissor Jack
     
  13. Rob Stone

    Rob Stone Junior Member

    Joined:
    Mar 7, 2008
    49
    15
    0
    Location:
    Portsmouth Ohio
    Vehicle:
    2015 Prius
    Model:
    ----USA----
    That’s a jack stand. We never rely on jacks to hold a car up.
     
  14. Rob Stone

    Rob Stone Junior Member

    Joined:
    Mar 7, 2008
    49
    15
    0
    Location:
    Portsmouth Ohio
    Vehicle:
    2015 Prius
    Model:
    ----USA----
    So my plan is to replace spark plugs and inspect EGR plus EGR tubing.
     
    amos, Raytheeagle and bisco like this.
  15. Rob Stone

    Rob Stone Junior Member

    Joined:
    Mar 7, 2008
    49
    15
    0
    Location:
    Portsmouth Ohio
    Vehicle:
    2015 Prius
    Model:
    ----USA----
    It still seems like a control module is not working right with traction control issue I am observing.....
     
  16. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    77,131
    32,446
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    do the intake mani while you're in there. how's the throttle body?
     
    amos likes this.
  17. Rob Stone

    Rob Stone Junior Member

    Joined:
    Mar 7, 2008
    49
    15
    0
    Location:
    Portsmouth Ohio
    Vehicle:
    2015 Prius
    Model:
    ----USA----
    Have not inspected yet. Will be weekend project.....
     
    bisco likes this.
  18. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    77,131
    32,446
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    wouldn't an eco give you a code?
     
    Rob Stone likes this.
  19. Rob Stone

    Rob Stone Junior Member

    Joined:
    Mar 7, 2008
    49
    15
    0
    Location:
    Portsmouth Ohio
    Vehicle:
    2015 Prius
    Model:
    ----USA----
    No lights on dash. Will read codes with my code reader this week.
     
  20. JC91006

    JC91006 Senior Member

    Joined:
    Nov 10, 2013
    13,472
    6,036
    0
    Location:
    Los Angeles, CA
    Vehicle:
    2005 Prius
    Model:
    II
    If there are no warning lights, it shouldn't be any failing electronic systems.

    I would do a whole tune up on the car.

    1. Change spark plugs
    2. Change coolant
    3. Clean EGR circuit
    4. Clean intake ports
    5. Clean throttle body
    6. Change pcv valve

    All in a days work
     
    Rob Stone and amos like this.
Loading...