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P0300 Misfire - Bad Headgasket?!

Discussion in 'Gen 3 Prius Technical Discussion' started by Sdolla86, Aug 11, 2024 at 9:36 AM.

  1. Sdolla86

    Sdolla86 New Member

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    Vehicle:
    2013 Prius c
    Model:
    III
    Hi All,

    Posting here to get some opinions.

    I have 2013 with 160k miles and got a misfire code. The car has a rough idle but runs fine at higher RPM (1.5k+). No smoke or leaks. Took apart the Egr valve, cooler and intake manifold and cleaned everything (probably could have done a better job for the intake manifold). No change in performance.

    Changed the spark plugs after and didn’t see an improvement. I did a compression test and all four cylinders were between 155-165. I understand I can still do a leak down test but my oil and coolant both look fine.

    I’ll probably buy the coil packs soon - just wanted to get some thoughts here ? Could some of the passages be clogged on the intake?
     
    #1 Sdolla86, Aug 11, 2024 at 9:36 AM
  2. Mendel Leisk

    Mendel Leisk Senior Member

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    Oct 17, 2010
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    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Always, or in particular with cold starts, then it smooths out?

    Coolant level in reservoir not dropping?

    I’d hold off on any more plug/coil replacements.
     
    #2 Mendel Leisk, Aug 12, 2024 at 6:36 AM
    Last edited: Aug 12, 2024 at 7:16 AM
  3. Tombukt2

    Tombukt2 Senior Member

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    Location:
    Durham NC
    Vehicle:
    2009 Prius
    Model:
    Base
    You're heading to engine dismantling You might want to hold up on firing the parts cannon many have done this here and you can read all about it The parts cannon is usually not a thing to be firing especially with this model there's too many things to go really wrong
     
    #3 Tombukt2, Aug 12, 2024 at 8:45 AM
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