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Prius engine shaking at 35mph

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Davidude, Aug 15, 2017.

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  1. Davidude

    Davidude Junior Member

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    My friend has an 08 Prius with 199k miles on it. I've been driving it recently, and I noticed an odd habit. When the engine is hot, driving 34-38mph while lightly accelerating the engine shakes as if it's about to die, but giving it more gas or simply coasting it goes away. The reason I ask is I'm considering buying the car from him. What do you guys think the problem could be? I want to get an idea of what it could be before visiting a mechanic. Original battery and oil was changed 2k miles ago, it has plenty.
     
  2. fotomoto

    fotomoto Senior Member

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    First thing I'd check: clean the throttle body and MAF sensor.
     
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  3. coolioe93

    coolioe93 Junior Member

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    As said above, I would start by cleaning throttle body and maf sensor.

    It could also be bad gas. Does it happen even after you've refueled?


    iPhone ?
     
  4. edthefox5

    edthefox5 Senior Member

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    Bad news is the onboard sensors are really good about any failures with the exception of internal damage like a spun bearing or low engine oil damage.. So hopefully it has a check engine light on or any other type of alert light on the dash. If there's a light on that usually means it's detecting a misfire.
    If not that's kinda bad. That means there's something mechanically wrong.

    Check the engine oil. And has the check engine light ever came on because the engine ran out of oil?

    Go on you tube and search Prius inspection mode. Put the engine in that mode and engine will run continuously. Listen carefully to the engine for bad noises like thumping or banging. Crawl under the front of the car while it's running and listen, to the engine.
     
  5. SFO

    SFO Senior Member

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    Any knowledge regarding the vehicles maintenance/tune up history?
     
  6. Ingrid Ramos

    Ingrid Ramos New Member

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    I am having the exact same problem with my 2008 Prius now, this just started a fee days ago and the check engine light is on. Any ideas on what it could be? The engine light goes on and off and the shaking does also as I accelerate or just coast the vehicle, your help is appreciated.
     
  7. dolj

    dolj Senior Member

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    Well, your symptoms are not exactly the same as you have the shaking/flashing when coasting whereas with the OP the shaking/flashing stopped when coasting.

    If I had to guess, it sounds like your car is misfiring on one or more cylinders. Having the car scanned for codes and also looking at the misfire codes for each cylinder. That would be the best way to confirm what specific problem your car has.
     
    #7 dolj, Apr 8, 2023
    Last edited: Apr 9, 2023
  8. douglasjre

    douglasjre Senior Member

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    Mil on? Usually coil pack or plug. Assume nothing though. Maybe EGR valve sticking?
     
  9. dolj

    dolj Senior Member

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    Does the Gen 2 even have an EGR valve?
     
  10. JC91006

    JC91006 Senior Member

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    I would check the following

    1. Air filter condition
    2. throttle body cleaniness
    3. maf sensor cleaniness
    4. condition of the spark plugs/coils
     
  11. edthefox5

    edthefox5 Senior Member

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    No.
     
  12. edthefox5

    edthefox5 Senior Member

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    Its showing codes so codes are being stored. Like Dolj said sounds like misfires.

    I would at least check the oil level. And have you ever ran the engine oil so low the check engine light came on?

    One of the common things that happen is the valve cover gasket fails and allows oil into the spark plug wells (holes) and will foul the spark plug boot and cause a missfire.

    I don't think its failed coil on plug (cop) becasue when they fail this engine makes a really loud racket like the engine is blown..

    Go on youtube and look up the Gen 2 Prius videos.Lots of videos about missfires.

    Go on Amazon and buy this OBD code reader it can be a life saver all you do is plug it in. And it will show you why the car is unhappy. I have this one it works good. It will not show hybrid codes like a bad hybrid battery but will show all the engine and emission codes.

    If you brought the car to the dealer that's the first thing they would do is pull its OBD codes and charge you $150 to do it.

    For $30 this code reader will pull the code then post the code here and we will help you. You can also clear codes too. Without the codes its all just a guess.like how many miles on your car and how long have you owned it???