Random Engine Shutdown/Low Power

Discussion in 'Gen 2 Prius Main Forum' started by BuckleSpring, Apr 11, 2026.

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  1. BuckleSpring

    BuckleSpring Member

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    IMG_20260417_182923_392.jpg

    Ordered 1-4, left to right. Nothing particularly weird, usual small amount of residue from oil burning as to be expected, but not bad considering they're ~50k miles old (If I'm remembering correctly).

    As for mileage, it's part of the 299,999 club, probably around 320-330k if I had to guess.
     
    #21 BuckleSpring, Apr 17, 2026 at 6:56 PM
  2. Brian1954

    Brian1954 Senior Member

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    Thank you for the picture of the spark plugs and the car mileage. What brand and type of spark plugs are they?
     
    #22 Brian1954, Apr 17, 2026 at 7:34 PM
  3. BiomedO1

    BiomedO1 Senior Member

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    2-4 looks a bit ashy, so burning lean. FWIW; they should look closer to #1; but it could just be the lighting of the picture. Are those plugs iridium and are those electrodes edges supposed to be rounded like that? I don't see the wire, unless they just put a drop of it on the electrode tip. I'm used to seeing a small iridium wire sticking out.
     
    #23 BiomedO1, Apr 17, 2026 at 7:35 PM
  4. BuckleSpring

    BuckleSpring Member

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    They're Densos, I couldn't tell you the PN#, my brother changed them 50k+ miles ago when he was borrowing the car for a couple of months.

    It's just the lighting, they're all identical in person.

    Either way, I don't get a change in misfire count in the live data at varying load/rpm, so I don't think the plugs are the particular cause of this issue.
     
    #24 BuckleSpring, Apr 17, 2026 at 9:19 PM
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  5. dolj

    dolj Senior Member

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    To my eye, that gap is too large. For 50,000 miles, those plugs look burnt out, so I wouldn't be surprised to learn that the 'iridium' tips were not iridium.

    I've pulled real Denso iridium tips after 100,000 miles, and the length of the tips looked almost new. I checked them, and they were still in spec. You need to check the gap with feeler gauges, they should be 1.0-1.1 mm, max 1.2 mm (I can't remember the old units off the top my head, sorry.)
     
    #25 dolj, Apr 18, 2026 at 12:04 AM
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