P0304 MISFIRE ON CYLINDER 4

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Catalinux, Feb 13, 2013.

  1. JC91006

    JC91006 Senior Member

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    Change the plugs and go from there. These turd gen cars have been going through head gaskets right around the mileage you're at now.

    Clean out the egr system while you're in there
     
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  2. Dan05979

    Dan05979 Junior Member

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    I'm watching youtube videos from "nutzaboutbolts" on how to clean out the intake & egr. Going to attempt to clean out all that besides changing the plugs. Lets see what happens. Besides this new problem, I'm experiencing that common problem of burning oil every 3K miles which is insane and toyota wants to take no responsibility on.
    About the head gasket....I pray i don't have that problem anytime soon.
    Thank you.
     
  3. JC91006

    JC91006 Senior Member

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    You having a 2010, around the 150k miles mark.....head gasket problem is pretty high
     
  4. Dan05979

    Dan05979 Junior Member

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    you have an idea on costs?
     
  5. JC91006

    JC91006 Senior Member

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    Most people are replacing engines when the head gasket goes. The engine costs vary around the country, dealers are quoting $5000.

    DIY head gasket repair and rings (to address oil burning), about $300-$400 with parts from rockauto. We have a very good thread on that from member Danlatu

    Don't get too worried right now, it could be simple plugs, coils, dirty throttle body...anything at this point
     
    #45 JC91006, Sep 13, 2017
    Last edited: Sep 13, 2017
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  6. mjoo

    mjoo Member

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    Beating my drum today...

    One of the purposes of the EGR system is to lower the combustion temperature from 2100*C to below 1726*C (2000*K) to prevent the formation of NOx. A completely clogged EGR system on a 2zrfxe Prius engine will increase the combustion temperatures by roughly 800*F. Engines that are run hotter than their design specs will adversely affect engine life.

    For the math, check out my reply in the EGR blanking plate ? thread.

    Cleaning the EGR/intake/combustion chamber components every 5-6 years will cost way less than installing a new engine. The EGR cooler takes multiple daily chemical soaks/rinses to remove all deposits from it. That's why I keep a clean spare in my garage.

    Used/old break fluid works great at dissolving the carbon. So does diluted purple power, diluted vinegar and oxyclean, etc.
     
    #46 mjoo, Sep 13, 2017
    Last edited: Sep 13, 2017
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  7. Dan05979

    Dan05979 Junior Member

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    I will be getting busy very soon with this repair. Do you think i can still drive with this condition or should i juts park the car?
     
  8. mjoo

    mjoo Member

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    I wish I could tell you. You could guess at how bad it is by removing the EGR-to-intake manifold pipe. This pipe takes about a half hour to remove. PC'ers say if there's much restriction there the cooler is plugged. As far as when you should park the car - if you have a second car I'd use it. Anything else is a gamble.

    Pixel XL ?
     
    #48 mjoo, Sep 13, 2017
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  9. Dan05979

    Dan05979 Junior Member

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    i'm going to use the car 1 more day and then transfer all my stuff to my 5 series thats in my profile pic. I really don't want to use that car but i have no choice. my drive is 150 miles round trip a day. I'll get cracking with this car on sunday. ugh...
     
  10. JC91006

    JC91006 Senior Member

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    if the misfire is consistent and not intermittent, it may just be a bad spark plug or coil
     
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  11. Dan05979

    Dan05979 Junior Member

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    I left work this morning (2am) and the violent shaking was bad. Then the CEL came on and the shaking went away. Drove home (70 miles) no problem. Drove to Autozone this morning around 10am and i was noticeable but very very softly. I'm going to drive it to work tonight to see how it makes out.
     
  12. JC91006

    JC91006 Senior Member

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    Violent shaking, hmmm so the symptom is there already. Yikes
     
  13. Dan05979

    Dan05979 Junior Member

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    yeah, i thought the motor was going to explode.
     
  14. JC91006

    JC91006 Senior Member

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    There's an extended warranty for that, not sure the timeframe on the extension though.

    But from what I read, the extended warranty doesn't really fix the problem completely
     
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  15. mjoo

    mjoo Member

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    It's a common symptom with the Prius. A number of us, me included, cured this by cleaning the intake manifold and installing an oil catch can. Without the OCC it comes back. Check out @danlatu's Oil Catch Can thread.


    Pixel XL ?
     
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  16. Raytheeagle

    Raytheeagle Senior Member

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    Have you checked the engine coolant level? Is it stable or dropping?

    All plug connections are tight and there are none loose on the top?

    Good luck with your cleaning:). I've done the job 3 times now. It is not time consuming or difficult, but fiddly, particularly around cooler removal :(.

    But a good weekend project.

    Keep us posted (y).
     
  17. Dan05979

    Dan05979 Junior Member

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    What's up guys, its day 2, been driving it, so far I'm getting some shimmering at low rpms, from stop lights to around 40 then it goes away at highway speeds. Going to park the car on saturday and start removing pieces to get to the intake, egr and spark plugs. Doesn't' look that difficult. its just time and patience i need. I'll keep you updated. Enjoy the weekend.
     
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