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2014 model suddenly running rough

Discussion in 'Gen 3 Prius Main Forum' started by Jim Caldwell, Mar 13, 2023.

  1. Jim Caldwell

    Jim Caldwell Member

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    Its at 188k miles. Several thousand miles ago it was running rough. Had Cyl# 1 misfire, and the "shudder of death" on initial cold start of engine. I cleaned entire egr system, and then the engine ran like new again. The codes being set now are:
    #1 cyl misfire
    # 1 Cyl fuel/air mismatch
    #2 cyl misfire
    Coolant level doesnt appear to have dropped.
    The spark plugs and coils were all replaced at abt 150k. I replaced water pump and pcv valve when egr was cleaned also.
    Im thinking from the way its shudders so strongly at lower speeds while accelerating that #1 and #2 cyl are not firing at all! How should I proceed with troubleshooting?
     
  2. mjoo

    mjoo Senior Member

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    Leak-down test

    moto g power ?
     
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  3. KamiKKazi

    KamiKKazi Member

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    I hate to say it but this is sounding like the beginning of a head gasket leak. Monitor you coolant it may probably start to go down more over time and then you will know for sure.
     
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  4. Mendel Leisk

    Mendel Leisk Senior Member

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    If it’s running true to course: it’ll be head gasket failure at the adjoining wall between cylinders one and two. EGR cleaning should be done every 50k; late in the day as you have done can’t turn back the clock.

    leak down test to confirm, then replace head gasket, new head bolts to play it safe.
     
  5. Jim Caldwell

    Jim Caldwell Member

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  6. Jim Caldwell

    Jim Caldwell Member

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    Well, can someone give me an idea as to what a head gasket job should cost. Of course if its a Toyota stealership, I realize it will probably cost 2x an independent garage ;-).
     
  7. bisco

    bisco cookie crumbler

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    Around two grand
     
  8. sam spade 2

    sam spade 2 Senior Member

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    I wonder why nobody has suggested inspecting the #1 and #2 plugs ?
    And inspecting the oil dipstick and inside of the filler cap for white "foam" ?
    The evidence is all circumstantial at this point but actual evidence, or lack of, should be fairly easy to find.
     
  9. bisco

    bisco cookie crumbler

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    Were the sparks oem from a dealer?
     
  10. Eddie25

    Eddie25 Active Member

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    By entire EGR system do you also mean the intake manifold EGR runners?

    I would check the spark plugs visually. If you bought your spark plugs off ebay, then that's it (the problem). Same with the coils probably, do you have your old ones? While checking your plugs you can swap coils around as a quick check, or if they aren't OEM or not from a trusted dealer then I'd just swap the old ones back (if they were working when you removed them).
     
  11. Jim Caldwell

    Jim Caldwell Member

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    Denso irridium I think.....its been a while. Yes, i confirmed ive got some steam coming out of tailpipe and drops of water.
    So I decided I and my son will do the head gasket replacement. I checked Autozone and there are many manufacturers of head gaskets to choose from. Felpro is one.....what is the best one to buy?
     
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  12. rjparker

    rjparker Tu Humilde Sirviente

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    (yesterday at 8:28pm)

    Never does "apparently" lose coolant at first but the severe rattles are an early warning. Initially the leak only occurs overnight and the engine seals it up when started.

    ...because most of us have been there and done that....

    (today at 10 pm)

    Sorry for your loss... Felpro. Be careful when you check the head, piston height and block, too many have learned another lesson by the second or third time.
     
    #12 rjparker, Mar 14, 2023
    Last edited: Mar 14, 2023
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  13. DPri

    DPri Junior Member

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    50K? May I ask how did you come up with that number?
     
  14. DavidDavid

    DavidDavid Junior Member

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    Clean your intake manifold
     
  15. PTS

    PTS Junior Member

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    He was eating magic mushrooms in his younger days and had a revelation. The Jehovah Witnesses did the same thing but their premonitions failed on many occasions.
     
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  16. rjparker

    rjparker Tu Humilde Sirviente

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    It is certainly not a Toyota recommended interval. However, it is a bit of a priuschat mantra. It's not an easy job and will cost almost $1000 if done at a dealer. So the reality is most EGR and intake cleanings are done DIY by chanting priuschat readers.

    A compromise position is to ignore it if your gen3 engine is not burning oil. However, if the engine is one of the excessive oil burners, oil will carbonize in the EGR cooler and the intake passages. In that case, 50k mile intake and EGR cleanings may be warranted.
     
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  17. Mendel Leisk

    Mendel Leisk Senior Member

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    Personal experience. 50k miles will see somewhere between light to moderate carbon build up.
     
  18. jerrymildred

    jerrymildred Senior Member

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    IIRC, the shop I just retired from charges about $600 for an EGR service.

    After cleaning about a thousand of them (and removing and replacing dozens). I'd agree that 50k miles is way too soon unless it's an oil burner. I just cleaned one for a friend that had 147k on his 2010 and it just blew out with an air hose and then some pressure washing. It was used, but it didn't seem like it had been out of there before. (NO ONE replaces the nut from hell! :LOL:)
     
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  19. Mendel Leisk

    Mendel Leisk Senior Member

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    Ok, 100k for first, then 50k thereafter? That would sync with the miles component of engine coolant replacement schedule. Maybe do the plugs a little early while the wipers and cowl are off, for expedience?
     
  20. Raphael Muscarelle

    Raphael Muscarelle Active Member

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    Based on my experience last week. I would check the sparkplugs. I just found 4 new bad oem spark plugs.
    I would also check resistance of the coils.
    New doesn't meen good.
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