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Slight hesitation at slight accel or constant speed

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by SinGarage, Nov 19, 2015.

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  1. SinGarage

    SinGarage Junior Member

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    New to the forums. I have a 2010 with about 166k miles. I am getting a slight hesitation at slight acceleration or constant speed. It does not matter if it's on highway or freeway speeds. Now I am not sure if this in junction with me changing the PCV valve, cleaning the EGR pipe, or cleaning the TB for carbon recently. It started happening a week after it though. Any help would be greatly appreciated.
     
    #1 SinGarage, Nov 19, 2015
  2. bisco

    bisco cookie crumbler

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    welcome! no codes?
     
    #2 bisco, Nov 19, 2015
  3. SinGarage

    SinGarage Junior Member

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    Thank you! And yes, no codes. The hesitation is like getting a tankful of bad gas.
     
    #3 SinGarage, Nov 19, 2015
  4. bisco

    bisco cookie crumbler

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    sorry, i'm no expert. some have mentioned excess cleaning fluid in the throttle body.
     
    #4 bisco, Nov 19, 2015
  5. SinGarage

    SinGarage Junior Member

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    No worries. Definitely no fluid as I cleaned the throttle body with lint-free rag soaked in TB cleaner. Now I did open the butterfly with my fingers. Not sure if I messed something up. It didn't feel like it's spring loaded like normal cars but more like actuated by an electric motor.
     
    #5 SinGarage, Nov 19, 2015
  6. bisco

    bisco cookie crumbler

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    you're description of low speeds are with the engine running?

    sorry, misread. high speed with slight acceleration, but enough for ice to come on?
     
    #6 bisco, Nov 19, 2015
  7. SinGarage

    SinGarage Junior Member

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    That is correct. It does not matter also if the engine is warm or cold. I am really stumped on this. I've had this car since 84k miles and this is the 1st time I have experienced this.
     
    #7 SinGarage, Nov 19, 2015
  8. bisco

    bisco cookie crumbler

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    have you done all required maintenance?
     
    #8 bisco, Nov 19, 2015
  9. SinGarage

    SinGarage Junior Member

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    Yup. I am very diligent when it comes to my daily drivers. My toys on the other one....eehh not so much lol.
     
    #9 SinGarage, Nov 19, 2015
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  10. bisco

    bisco cookie crumbler

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    fuel injectors? i'm just thrown' stuff out there.:p
     
    #10 bisco, Nov 19, 2015
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  11. m.wynn

    m.wynn Senior Member

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    Have a look through through this thread, and notice my 1st post in it for a link to another thread with some pics of the intake manifold EGR ports cleaning. You're likely on the right track with the EGR pipe, you just need to follow it's path the entire length of the IM.

    missing under light throttle | PriusChat

    You cleaned the MAF when you did the TB?..
     
    #11 m.wynn, Nov 19, 2015
  12. SinGarage

    SinGarage Junior Member

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    I've actually seen that thread and that's how I got to cleaning the TB, EGR pipe and ports. I did not however take off the IM or cleaned the MAF. I will try cleaning the MAF. In all honesty though, the pipe and ports weren't too bad as I was expecting worse with 166k miles.
     
    #12 SinGarage, Nov 19, 2015
  13. SinGarage

    SinGarage Junior Member

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    After looking at all the other links, it's probably be best if I take off and clean the IM and EGR just in case. I really appreciate the answers. Will keep everyone posted and if anyone else have a suggestion, please let me know. Thanks!
     
    #13 SinGarage, Nov 19, 2015
  14. SinGarage

    SinGarage Junior Member

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    Ok so I finally took off the intake manifold and was not surprised with all the crud on it (see pics below). What surprised me is the puddle of oil underneath the TB. It was a little alarming to find that much oil, at least 2-3 ounces. After cleaning out, I am not getting the surge or hesitation on constant speed anymore but it is still early to tell. Will update if any other changes. Again thank you to everyone who has helped.

     
    #14 SinGarage, Dec 1, 2015
  15. A617

    A617 Member

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    Thats some serious excessive build up, on what i'm assuming is, on your fuel injector hole?

    A few questions if I may ask
    What's your oil mileage change intervals
    What oil brand and weight do you use
    Driving habit...Ie hard or easy driver, both.
     
    #15 A617, Dec 1, 2015
  16. SinGarage

    SinGarage Junior Member

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    I believe they are the EGR lines that feed backs into the IM.

    I change my oil every 5k with either Valvoline or Mobil 0W/20 Full synthetic.
    I know it's supposed to be 10k intervals but the oil is very contaminated by 5k.

    I do a little of bit of both but more city driving now that earlier in its life.
     
    #16 SinGarage, Dec 2, 2015
  17. Mendel Leisk

    Mendel Leisk Senior Member

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    Have you followed the EGR circuit all the way back to the exhaust manifold, removed and cleaned that last component? That looks to be a bear, has 4 coolant lines attached, and access not that easy. It has an internal grid the coolant flows through, to cool exhaust gases as they're coming through.

    Someone here with similar mileage removed that, and found it so totally clogged he elected to replace it.
     
    #17 Mendel Leisk, Dec 5, 2015
  18. HGS

    HGS Member

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    Finding the root cause can be a bear sometimes. It sounds like you've been averaging 25-30,000 miles/year. High annual mileage cars always interest me because I drive about 20,000 miles/year and wonder what I can expect.

    Do you have a Mini VCI cord with diagnostic software? Sometimes diagnostics can find problems that are not coding yet. I bought my Mini VCI cord on Amazon for <$25. (?). You can find the software for free online, or pay Toyota a fee to use their official software.

    image.jpeg
     
    #18 HGS, Dec 5, 2015
  19. SinGarage

    SinGarage Junior Member

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    Are you talking about the EGR in itself or another component in between the EGR and the exhaust manifold? I did not clean it as I just wanted to see if the cleaning of the IM will cure the issues I have first. It only takes me about 10-15 minutes to get the IM off now lol.
     
    #19 SinGarage, Dec 7, 2015
  20. SinGarage

    SinGarage Junior Member

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    This is the 1st issue as of yet. Usually just change oil, check fluids, and regular maintenance. I do not have a Mini VCI cord or diagnostic software as I never really had to since it's been reliable. Maybe I should invest in one now lol. What is the name of the freebie sofware?
     
    #20 SinGarage, Dec 7, 2015
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