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P0300 Code with Coolant Loss

Discussion in '1st Gen. Tacomas (1995-2004)' started by ToyTaco02, Feb 25, 2020.

  1. Feb 25, 2020 at 10:13 AM
    #1
    ToyTaco02

    ToyTaco02 [OP] New Member

    Joined:
    Feb 25, 2020
    Member:
    #320319
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    Male
    All,

    I recently had to replace my radiator on a 2002 V6 Pre-Runner (177,500 miles). That is when the P0300 started to appear. I changed the plugs, wires & boots. Cleaned the Mass AirFlow Sensor and since had a mechanic tell me that most of the misfires are in #4.

    Since the radiator change, the coolant reservoir has been loosing volume every few days.

    The motor rough idles at start up and seems to stop at 2,000 rpm's and when it is at running temp. (my OBDII reader says 200°). I thought running temp should be 180°?

    Any thoughts and thank you in advance for your replies.

    Regards,

    ToyTaco02
     
  2. Feb 25, 2020 at 8:37 PM
    #2
    cruisedon66

    cruisedon66 Well-Known Member

    Joined:
    May 9, 2016
    Member:
    #186469
    Messages:
    666
    Gender:
    Male
    First Name:
    Pete
    Near St. Louis
    Vehicle:
    2003 Tacoma Extra Cab 2WD A/T
    Defrost mirrors, compass/temp display rear view mirror, rear wiper on camper shell, trans.cooler.
    I'd put the old wire back on #4 just to see if the miss goes away.

    As for the coolant loss. It can only be a faulty /loose hose clamp. As it wasn't there before.
     
  3. Feb 26, 2020 at 9:25 AM
    #3
    ToyTaco02

    ToyTaco02 [OP] New Member

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    Cruisedon66,

    Many thanks for the reply. I am also thinking about switching the coil pack(s) around to see if the miss moves with the coil.

    As for the coolant, there is no visible leakage under the hood or on the ground.

    The shop manager/mechanic, who told me where most of the misfires were coming from, stated that because the loss was coming after the new radiator was installed, maybe there is a head gasket issue?

    Regards,

    ToyTaco02
     
  4. Feb 27, 2020 at 7:39 AM
    #4
    cruisedon66

    cruisedon66 Well-Known Member

    Joined:
    May 9, 2016
    Member:
    #186469
    Messages:
    666
    Gender:
    Male
    First Name:
    Pete
    Near St. Louis
    Vehicle:
    2003 Tacoma Extra Cab 2WD A/T
    Defrost mirrors, compass/temp display rear view mirror, rear wiper on camper shell, trans.cooler.
    I'd check the rubber seal & fit of your Radiator cap. Antifreeze may be evaporating.

    Go for the easy stuff first.
     

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