Replacing spark plugs

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by avoice217, Dec 19, 2025.

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  1. CR94

    CR94 Senior Member

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    Couldn't unequal clogging of EGR ports of the manifold be a plausible culprit for "starting to shake while ... accelerating", even if the head gasket is ok?
     
    #41 CR94, Jan 4, 2026 at 4:39 PM
  2. ChapmanF

    ChapmanF Senior Member

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    As I understand things, shakes on initial startup, after sitting for a while, and quickly clearing up, would cast suspicion on the head gasket.

    Shakes while driving, if they are not present at idle and not present at full throttle, but show up at moderate loads when EGR is used, would cast more suspicion on the manifold EGR passages, and wouldn't be very consistent with a head gasket problem.
     
    #42 ChapmanF, Jan 4, 2026 at 4:44 PM
  3. avoice217

    avoice217 Member

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    Hey guys, let me put everything back together and take it for a drive. I certainly hope that its not the head gasket, but we shall see. I did notice at least 1 of the small holes clogged inside the intake manifold, so tomorrow I'm going to put the intake manifold back into the car and see how things go. I'm also going to inspect the pcv valve while I have to intake manifold out. I did watch a video on how to interpret the sound on that.
     
    #43 avoice217, Jan 4, 2026 at 7:49 PM
  4. ASRDogman

    ASRDogman Senior Member

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    You might as well replace the pcv valve while it's out. It's $10-15 part. And not fun
    to get it with the intake manifold on.....

     
    #44 ASRDogman, Jan 4, 2026 at 8:05 PM
    Mendel Leisk likes this.
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