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2004 Tacoma EVAP/Misfire

Discussion in '1st Gen. Tacomas (1995-2004)' started by rmanscott, Feb 12, 2025.

  1. Feb 12, 2025 at 6:07 PM
    #1
    rmanscott

    rmanscott [OP] New Member

    Joined:
    Feb 12, 2025
    Member:
    #465873
    Messages:
    1
    Gender:
    Male
    2004 Tacoma 3.4 - 242k miles

    I’ve been reading forums and racking my sack for a few weeks now. Can’t figure out why I’m getting the dreaded P0442 small leak EVAP code and a cylinder 3 misfire code.

    The weird part is my truck on a cold start runs fine. When it’s warmed up and I shut it off (for example when fueling it up or run into a store) and start it back up again, the mis fire presents itself. Sometimes, after driving for a random period of time, the misfire will go away and it runs fine. Sometimes the misfire doesn’t go away at all and won’t run normal until it’s a cold start again.

    Trouble shooting so far:

    - Replaced the gas cap (not Toyota but continue reading)
    - Replaced the charcoal canister (Toyota)

    I removed the bed and started testing.

    I bought a smoke tester and tested for leaks in the EVAP system from the EVAP purge valve under the hood going back to the charcoal canister. No leaks in the line going back but I did have smoke coming out the fuel filler neck plastic housing near the gas cap. Confirmed it wasn’t the gas cap but thought it was strange smoke was coming out of there. I followed the line back and it connected to the charcoal canister… which is why I replaced it. Issues is still persisting.

    I’ve tested the purge valve and it starts pumping after it warmed up.

    My next thought is maybe replacing the filler neck. Is it supposed to be allowing smoked coming from the EVAP system through the charcoal canister? Or is the filler neck needing to be replaced?

    I’m at a loss though. Any ideas or suggestions would be much appreciated.

    Note that I do smell gas fumes near the fuel door, so maybe it is the gas cap not being Toyota? But is it the filler neck released the fumes from the plastic housing near the top of it? Please help lol
     
    Last edited: Feb 12, 2025

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