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what could my problem be?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by ramattos, Apr 15, 2014.

  1. ramattos

    ramattos Junior Member

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    i recently felt i had an intermitent misfire on one cylinder but had no codes stored. this past weekend i decided to check the condition of my plugs as the car is at 98k miles. i saw that they looked worn and put them back. i drove around yesterday and the car was constantly missing but not enough to throw a code. today while driving it threw a code before i even put it in gear. drove to autozone and they checked the codes. all 4 cylinders are missing. is it possible that i broke something when i checked the plugs? or maybe its the plugs themselves. the only things i touched were the air handler, removed the 2 bolts and the 2 clamps and disconnected the MAF, but reconnected it properly. i also removed the relay box but doubt that would cause anything. and obviously the coils and plugs. and unless turning the engine by hand would cause something to get out of allignment im stumped.
     
  2. JC91006

    JC91006 Senior Member

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    Why would you put the plugs back at 98k miles? You already took them out and noticed they were worn.

    Did you tighten the plugs properly?
     
    edthefox5 likes this.
  3. Patrick Wong

    Patrick Wong DIY Enthusiast

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    1. Buy new NGK or Denso iridium spark plugs, model numbers as specified in the owner's manual
    2. Remove the four spark igniters and inspect them for damage such as cracks in the plastic body, rust marks, and replace as needed
    3. Remove the old spark plugs and discard
    4. Check that the new spark plug gap is 1.0 to 1.1 mm. Install the new spark plugs, tighten to 13 ft.-lb torque
    5. Install the spark igniters
    6. Inspect the wiring harness connectors and make sure there is no corrosion. Install the connectors to the igniters making sure they snap in place which locks the connectors.
    7. Check the MAF sensor wiring harness connector and make sure it is properly connected to the sensor.
     
  4. ramattos

    ramattos Junior Member

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    yes, and i was planning on replacing them in a few weeks when i get paid.
     
  5. JC91006

    JC91006 Senior Member

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    Maybe your issue is not spark plug related? what code was pulled?
     
  6. ramattos

    ramattos Junior Member

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    not sure of the exact code but the guy said it was a miss on each cylinder
     
  7. ramattos

    ramattos Junior Member

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    now a temporary solution, could i take the plugs out and close the gap a bit so i can make it home tonight and then get them later since the stores are closed when i get off work?
     
  8. JC91006

    JC91006 Senior Member

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    The battery gap should not be that off at 98k miles. Also re-gaping old plugs is not recommended, you can break them.

    I would try disconnecting the negative battery terminal to reset your car and see what happens.

    The correct spark plugs are:

    IFR5T11 (stock 4996) - I believe they are $8.99 at autozone.
     
  9. JC91006

    JC91006 Senior Member

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    I'm not sure the plugs are your problem. Many have replaced plugs at 120k and beyond and the plugs look really good at that mileage. I'm wondering if AutoZone has a proper reader that can read the codes from a Prius? It's very rare to have plug issues at 98k.
     
  10. ramattos

    ramattos Junior Member

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    if its not the plugs then what else as it wasn't like this before i removed them?
     
  11. JC91006

    JC91006 Senior Member

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    I would check all your connections first. Everything you touched, disconnect, check them, and reconnect.
     
  12. ramattos

    ramattos Junior Member

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    thanks, im gonna do that as when i first went to check them i didnt have the right tools and just put the igniters back on and had no problems.
    ive also been looking more and found something that could suggest other stuff such as the injectors, throttle body, MAF, pcv. but i didnt do anything to them that would cause the misfire
     
  13. ramattos

    ramattos Junior Member

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    Ok, I solved the problem. It seems that when I pulled the old ones to check them I cracked the ceramic on 2 of them. Replaced them all with ngk iridium IX, and I notice a 4-8mpg increase in one tank. Thanks for the help
     
  14. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I suggest that you buy a quality spark plug socket for future use. This deep socket will have a rubber insert which will help to protect the porcelain tail of the plugs.

    NGK Iridium IX is an OK plug, but do not expect it to last as long as the correct NGK or Denso plugs. The difference is that the original equipment iridium plugs have a platinum tip on the ground conductor to help maintain the correct gap of 1.0-1.1 mm.

    See the fourth FAQ here:
    Frequently Asked Questions: DENSO Iridium
     
  15. ramattos

    ramattos Junior Member

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    thanks, i did have one of those sockets but i think that when i took it out the torque on it cracked it. i wouldve gotten the ngk laser iridium but my local autozones were all special order and i couldnt wait