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Misfire? or Not!

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by SWprius08, Oct 6, 2014.

  1. SWprius08

    SWprius08 SoCalprius

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    So after doing some troubleshooting and researching in trying to find out on my 87K 2008 Prius Std "Noise in the engine while accelerating", "Approximately 10% reduction in fuel efficiency, due to lack of power from engine" & "Glide seems to be degrading over time", here is what I have observed.

    1) When I push the gas when the car is parked the engine does not seem to rev in a stream, it goes up for about 3 seconds then goes down for 1 second, then again goes up and then down and this keeps happening until the gas pedal is kept press. In conventional cars the rev should be streaming continuously and proportionately to the pressure applied on gas pedal. This almost seems like a misfire, but from the drivers seat I do not hear any blasts, I have never tried this before so I don't know if Prius's are suppose to be like this. Also no Alarms on the MFD.

    2) After using the 5.25 oz fuel injector cleaner in back to back half tanks I saw the engine regaining power and hence bettering the fuel efficiency. Does that mean I should get a Fuel Injector cleaning done by Toyota?
     
  2. Easy Rider 2

    Easy Rider 2 Senior Member

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    Only if it is still not running good.
    What kind of injector cleaner did you use ?
     
  3. SWprius08

    SWprius08 SoCalprius

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    STP. Got it from Arco gas station.
     
  4. Easy Rider 2

    Easy Rider 2 Senior Member

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    Probably decent for preventative use but maybe not for problem solving.
    Get a can of Berrymans B12 Chemtool and put in two ounces per gallon of gas; best done when the tank is half full or less.
    If that stuff don't clean the injectors, they might be beyond help........or there is something else wrong.
     
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  5. JC91006

    JC91006 Senior Member

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    If there's a misfire, your Prius will kick out a DTC. If there are no warning lights, there's probably nothing wrong with your car. In terms of less MPG, we are facing an extended heat wave/summer. The more you use your AC, the more you'll notice the mpg going down. In you recovering some MPG recently, it's most likely due to the weather cooling off and your AC is not blasting the entire time.
     
  6. SWprius08

    SWprius08 SoCalprius

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    Thank you very much Easy Rider 2 for valuable information. Will try it.

    Thanks JC for your note. Actually I was very concerned whether what I heard was misfire or not hence when I went to Meineke to get the transmission fluid change done ($100 labor + $ 45 oil & washer from Toyota) I asked the technician who also happened to own a Gen 1 prius. He laughed at my lack of knowledge (not in a insulting way) and told me that unlike a conventional car, prius has some kind of governing valve which does not let the engine go to very high RPM when gas pedal is pressed while in parked mode, hence after certain RPM it automatically goes low again. I am relieved!

    Regarding the Fuel efficiency I did consider the AC factor while checking the MPG, also I am in the SF Valley where the temperatures are still in mid 90's. Without a shadow of doubt the MPG went considerably up when I used 2 STP's back to back. Now with transmission oil change my Prius is back to normal, very excited to effectively troubleshoot the issue without going to the dealership at all. If the effect of STP will slowly wither away (in 2K to 3K per other posts) then I will follow Easy Rider 2's advise regarding the Berrymans B12 Chemtool.
     
    #6 SWprius08, Oct 8, 2014
    Last edited by a moderator: Oct 8, 2014
  7. Easy Rider 2

    Easy Rider 2 Senior Member

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    Looks like a little clarification is on order.
    B12 is an excellent heavy duty cleaner, so much so that I'm not sure I'd recommend it for routine use.
    For that, I use Techron......at a minimum of every oil change.
    SO.....if it appears that your car really IS back to running normally again, my recommendation is for a shot of Techron every 5K miles or so.
    If it goes back to running rough soon, then a dose of B12 would be in order.
     
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  8. SWprius08

    SWprius08 SoCalprius

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    Yup it is running very close to normal now. I will monitor it for next few days and use b12 only if needed, else will stick to techron at every oil change.
     
  9. bisco

    bisco cookie crumbler

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    you must have some seriously bad gas out there.
     
  10. SWprius08

    SWprius08 SoCalprius

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    i only use 87 arco. 87 was recommended by the sales rep of toyota wgen i was buying it. what is recommended by pc users?
     
  11. bisco

    bisco cookie crumbler

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    87, but i've never seen the need for additives around here, and i fill up at the cheapest place i can find.
     
  12. Easy Rider 2

    Easy Rider 2 Senior Member

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    The octane rating of gasoline is ******NOT****** a measure of it's quality.
    You can get "bad" gas in any octane rating.
     
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  13. dolj

    dolj Senior Member

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    Agree 100%, but you can't tell some people.
     
  14. SWprius08

    SWprius08 SoCalprius

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    So apparently the meineke mechanic either did not get my question right or I did not get what he was trying to tell me, as that misfire is not normal and the problem lied in a bad throttle body assembly, once replaced it the problem went away. If interested see this thread.
    2008 Prius losing power - Need troubleshooting help. | PriusChat
     
  15. bisco

    bisco cookie crumbler

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