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Cold start rough idle with misfire codes

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Uber_NYC, Jan 23, 2020.

  1. Uber_NYC

    Uber_NYC Junior Member

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    I wasn’t getting any coolant loss, oil looked good, ran the techstream compression test it was good.

    What I’ve done already to solve this
    - cleaned EGR valve and cooler
    - completely cleaned out intake manifold
    - replaced PCV
    - replaced spark plugs and ignition coils
    - replaced fuel injectors

    The ICE now has a rough start with 3 seconds of misfires then idles normally. While cleaning out everything I found very heavy carbon deposits inside the head itself and all over pretty much everything I cleaned out 59985823244__A3152542-D6D7-4F0E-844B-5466AC82C876.jpg

    Look at my old injectors
    60133866822__B8D2F2A1-2C87-45FF-BC0A-CA431FC2FB9C.jpg

    What can I do next? I was thinking of running the Berrymans total combustion treatment through the evap vacuum line.


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  2. bisco

    bisco cookie crumbler

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    how many miles on her?
     
  3. Uber_NYC

    Uber_NYC Junior Member

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    2013 with 100k miles


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  4. bisco

    bisco cookie crumbler

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  5. Uber_NYC

    Uber_NYC Junior Member

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    I didn’t use the best gas and there was a pinhole in the engine air filter where you could see dust was getting through. The carbon in the head was literally flaking off in some spots.


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  6. tankyuong

    tankyuong Senior Member

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    Did you get authentic spark plugs
     
  7. Uber_NYC

    Uber_NYC Junior Member

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    Yes, from the dealer. I saw the reports of fake plugs on Amazon.


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  8. Peter123

    Peter123 Active Member

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    Have you tried an engine cleaner, like Seafoam or Cataclean?
     
  9. mjoo

    mjoo Senior Member

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    After my EGR maintenance I left the head deposits alone and just used a few techron treatments. 2 years later the head had a light oil coating and no deposits.

    Good idea to remove and clean the injectors.

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  10. David Scott Dallas

    David Scott Dallas Junior Member

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    Did you clean the throttle body? I had rough engine shifts on and off while driving when the motor would kick on. while stationary the car would really move like someone had jolted it when the engine would kick on. I removed and thoroughly cleaned nothing but the throttle body and maf sensor and it ran so much smoother
     
  11. Uber_NYC

    Uber_NYC Junior Member

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    Yeah I cleaned the throttle body and the MAF and the MAP. Surprisingly the throttle body was the only piece that wasn’t covered in heavy residue.


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  12. Uber_NYC

    Uber_NYC Junior Member

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    I have Techron in there now. The first engine start is rough after 20 seconds every time. I turn off the car and it starts really smooth the next time. After an hour idling and a few really smooth engine cycles the misfires come back bad.


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    #12 Uber_NYC, Jan 26, 2020
    Last edited: Jan 26, 2020
  13. tankyuong

    tankyuong Senior Member

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    When it starts knocking apply the throttle until knocking disappears