2008 Prius ICE rocks during Idle/Take-off

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by jacinto1023, Sep 22, 2018.

  1. jacinto1023

    jacinto1023 New Member

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    Hello,

    I just purchased a 2008 Prius with 115xxx miles on it.

    i'm going to change the oil, oil filter, spark plugs, air and cabin filter.

    The only issue i have is the motor seems to shake. it only happens when the ICE turns on. So this happens on first startup, during idle when the ICE kicks in every now and then and when taking off and it kicks in.

    When ICE shuts off or during regular driving, its fine. i cant feel the difference when its motor or battery. Its really during idle when ICE kicks in and on take off when ICE kicks in.

    i'm hoping changing the plugs help but i'm wondering if its a motor mount issue? the car literally rocks back and forth a bit during idle when ICE kicks in and on takeoff it feels like a thud! I'm suspecting the front motor mount, the one that looks like a dog bone mount. Is there any thing else i should try? maybe cleaning the EGR system, run some sea foam?

    Thanks!

    #1
     
    #1 jacinto1023, Sep 22, 2018
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Start by replacing the iridium spark plugs using the correct NGK or Denso plugs. Replace the PCV valve. Use a deep socket on the PCV valve, do not use an open end wrench.

    Clean the throttle body interior and throttle plate by spraying throttle body cleaner on a cloth, and using the cloth to scrub the dirt off. Clean the mass air flow sensor using MAF cleaner spray.

    There is no EGR system.
    Then see whether the problem still exists.
     
    #2 Patrick Wong, Sep 23, 2018
  3. padroo

    padroo Senior Member

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    Good list Patrick, and put some fuel injector cleaner in your tank.
     
    #3 padroo, Sep 23, 2018
  4. JC91006

    JC91006 Senior Member

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    The car can feel a bit rough when it's warming up, it shouldn't have any shaking once it's fully warmed up.
     
    #4 JC91006, Sep 23, 2018
  5. edthefox5

    edthefox5 Senior Member

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    I think what your exoeriencing is quite normal. You probably have never driven a g2 before.
    There’s a big shake when the motor turns on and another when the motor shuts off.

    Many many posts here complaining the car jumps or moves when the engine turns on. The car does not move it’s just a big movement of the engine. The reason there’s a big shake is the transmission has to spin the engine to fire it up to be exact electric motor mg1. So you have big engine/trans components engaging simultaneously at the same moment so a lot going on in a blink of an eye.

    Normal and very discerning if not used too it.

    If the engine was unhappy it would throw a check engine light. Change the oil and install a high quality engine oil like Mobil one 5-30 full synthetic Buy a 5 gallon jug of that at Walmart for $25.

    The engine takes exactly 3.5 quarts with a new oil filter. Keep the engine oil at the full line.
     
    #5 edthefox5, Sep 23, 2018
    Raytheeagle and JC91006 like this.
  6. jacinto1023

    jacinto1023 New Member

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    Thanks everyone! I will do everything you guys suggested.

    So after driving the car for about two days now i've noticed that it is indeed rougher while first starting up and warming up but after 5-10mins its a lot smoother. you can barely feel the ICE kicking in or out.

    What i did notice is the shaking i'm referring to in my original post seems to be the transmission/big battery? its as if when i release the brakes the electric motor engages and the car jolts a bit. i can replicate it if i sit in drive holding the brake pedal and slightly tap the gas. the info screen shows big battery on snd the car will jolt like a broken motor mount.

    is the transmission going bad or normal?
     
    #6 jacinto1023, Sep 23, 2018
  7. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Don't worry about the transmission going bad yet.

    As part of your maintenance activities, drain and replace the transaxle ATF. Buy 4 quarts of Toyota ATF WS. The capacity is 3.9 quarts.

    At 100K miles, the engine coolant and inverter/transaxle coolant should have been drained and replaced, although that has nothing to do with the issue you raised. If you do not have a record that this was done, plan to do that as well. Use Toyota Super Long Life Coolant, you will need to buy 3 gallons as you will need ~6.5 quarts for the engine and ~2.5 quarts for the inverter/transaxle. Keep track of the amount of drained fluid, and make sure you add at least that amount back in new fluid. You will know that you have air in the system if you are not able to add the same amount back as drained.
     
    #7 Patrick Wong, Sep 24, 2018
    jacinto1023 likes this.
  8. jacinto1023

    jacinto1023 New Member

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    Thanks! I will drain and replace all fluids and oils.
     
    #8 jacinto1023, Sep 24, 2018
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