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Help diagnosing two issues 1) misfiring/stumbling 2) coolant loss

Discussion in 'Engine & Drivetrain' started by John03Z71, Dec 18, 2020.

  1. andzac

    andzac TYF Newbie

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    I had a similar problem with my 04 yukon cutting out on acceleration,I cleaned throttle body which helped a bit. I then changed sensor on gas peddle and it hasn't cut out in 4 months...knock on wood!
     
  2. Old Goat

    Old Goat TYF Newbie

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    Low coolant problem.

    Run your fingers around the heater core connections on the firewall. That's where my 05 Tahoe was slowly leaking.
    Replacements for those are readily available ay O'rielly's.
     
  3. John03Z71

    John03Z71 Member

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    Thanks for all the replies. I haven’t had much time to focus on this since the holidays, but the misfiring / hesitation issue reared its ugly head last night by finally throwing a P0301 code, and it got realllllly bad during one acceleration period that caused the check engine light to start flashing. I shut the engine down and gave it a minute then limped back home (not in limp mode, but basically went super easy on the pedal). Also P0442 is showing up twice. Im not sure they’re related though.
    Any suggestions on where to start with P0301?
    i put in new plugs and wires a few years ago, the slight misfiring / stumbling issue has been consistent for several years so I’m not sure a new plug or wire will fix it... it might just foul up the new plug and wire. They all probably need to be replaced again due to being fouled up from the misfires but I’m still n out getting to the root cause. Any suggestions besides plug and/or wire would be much appreciated, from a budget friendly DIY perspective vs throwing parts and money to see what sticks. Thanks again for all the helpful input.
     
  4. PNW VietVet

    PNW VietVet Supporting Member

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    The P0301 code is a misfire in cylinder #1. I would pull that plug and the one next to it, #3 plug, and compare and get pics of both here.

    The P0442 code is "P0442 indicates that you have a small leak in the evaporative emission system. Many times this is caused by a loose or faulty fuel cap. ... The P0442 error code is an evaporative emission control code and is an indication of a small leak being detected in the evaporative emission system."

    Check this link out: https://www.engine-codes.com/p0442_chevrolet.html

    The coolant loss could be related to the misfire in #1 cylinder because of a head gasket problem. Again, could be.
     

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