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Misfiring mystery on Gen 2 (2008)

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Many Prii guy, Feb 11, 2020.

  1. Many Prii guy

    Many Prii guy New Member

    Joined:
    Jan 14, 2020
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    Location:
    Charlotte, NC
    Vehicle:
    2008 Prius
    Model:
    ----USA----
    Sorry, I'm late here. I too have had this problem for more than 6! I've bought and replaced all coils spark plugs injectors ECU oil and coolant. I too had evap codes that turned out to be the fuel filler neck had rusted holes in it. I replaced that and never had an evap problem again. But the pesky random misfires have been there for nearly the whole 7yrs I've had the car. I know a good bit about cars and can do all my own work but without the right diagnostic tools, I have not been able to figure this one out. Never got around to taking it to Toyota for it. So if anyone finds a solution it would be greatly appreciated. Id also like to note that The front left wheel bearing in this car is BS! I've paid over 700 dollars to have this same wheel bearing replaced like 3 times in my 01. I just bought and 08 Prius and low and behold the front left wheel bearing has the same problem but I'm not about to keep having this thing replaced! I need some solutions! By the way the last time I finally let Toyota replace it and it only lasted about 3 months before it needed replaced again. They charged 345 to replace it.
     
  2. Many Prii guy

    Many Prii guy New Member

    Joined:
    Jan 14, 2020
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    Location:
    Charlotte, NC
    Vehicle:
    2008 Prius
    Model:
    ----USA----
    Someone mentioned the filler neck rusting allowing dirty rainwater to get into the gas tank and cause misfires in the 2001 to 2003 year model. My 01 have the same issue but my filler neck also had to be replaced a long time ago but I still have the misfire problem. Another person mentioned his problem was solved by replacing the actual wires to the injectors. I guess they had a short in them due to harsh weathering. I've replaced nearly the whole engine trying to find this problem so the wires will be what I try next. Also for me I actually suspect a compression problem possibly because I have over 350k miles.
     
  3. edthefox5

    edthefox5 Senior Member

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    Location:
    Clearwater, Florida
    Vehicle:
    2007 Prius
    Model:
    Two
    Wow lots of miles.

    So is the car throwing P3000 codes or you just can feel it’s slightly misfiring?

    Put it in inspection mode and let it run and see how it runs. Let it run for a while till it’s warmed up. If idles smooth that means it only does it under load and engine probably just worn out. Lots of engine swaps on this site.

    Go on YouTube search Prius inspection and it will show you the chicken dance for inspection mode where the engine will idle continuously till shut off.
     
  4. edthefox5

    edthefox5 Senior Member

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    Vehicle:
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    Two
    Btw never heard of rusted out fuel pipe. Been here for 12 years. Thats odd.
     
  5. M in KC

    M in KC Active Member

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    Vehicle:
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    Go to your local auto parts store and check-out their compression tester kit through their loan-a-tool program. The age, symptoms, miles and replaced parts to date would certainly suggest low compression is in the realm of possibilities. Quick and simple test on these mills.
     
  6. Barry CLEMENTS

    Barry CLEMENTS Junior Member

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    You mentioned changing coolant but you didnt mention whether you replaced the coolant temperature sensor. If the sensor is bad, you will have brief periods where the engine runs smooth but once that temp sweet spot has changed, misfires will continue. The sensor sends readings to the ECU as part of the feedback that computes air/fuel mix. So, a bad coolant temperature sensor, whole an easy fix, may also be easily missed .