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Intermittent P0420

Discussion in '1st Gen Tundras (2000-2006)' started by F1reheart, Aug 30, 2017.

  1. Aug 30, 2017 at 11:15 AM
    #1
    F1reheart

    F1reheart [OP] Love my Tundra

    Joined:
    Aug 17, 2017
    Member:
    #9112
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    Female
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    2003 SR5 4.7
    I started seeing this error in my code scanner about a month ago. I tried some Seafoam, and the check engine light went away.....then came back a week later. Another can of seafoam - check engine light stayed on.

    Today I came back from a 4 day holiday, started it up and the engine light was OFF. Now what! Am I dealing with bad oxygen sensors (no codes for them are appearing), stuck fuel injectors (short term and long term readings look pretty good) or a weird catalytic converter? It's a 2003 4.7L with about 98k miles. Suggestions, before I starting spending my hard-earned dough?
     
  2. Aug 30, 2017 at 5:45 PM
    #2
    kenomouth64

    kenomouth64 New Member

    Joined:
    Oct 28, 2016
    Member:
    #5015
    Messages:
    863
    First Name:
    Tetrus
    Vehicle:
    2007 Toyota Tundra Sr5 4x4 (TRD Off Road) Crewmax 5.7L
    Hold the Line! If you are not holding the line, abandon your ship. Destruction is inevitable without more to hold the line!
    I would replace the Oxygen sensors just before and after the Cat(s). I would not imagine the catalytic converter is already 'worn out' with just 98k miles. Every time I have ever seen the trouble code come up it is resolved by either cleaning the cats or replacing them.
     
    F1reheart [OP] likes this.
  3. Aug 31, 2017 at 4:16 AM
    #3
    Wynnded

    Wynnded What MPG...

    Joined:
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    3,733
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    Rockies
    Vehicle:
    2011 RCSB S/C'd 5.7L AWD Tundra
    OEM Upgrades: TRD PRO BBS Wheels TRD S/C, OVTune and +2 psi pulley TRD Rear Sway Bar Fox TRD Pro Shocks Limited mirrors (auto darkening/backup camera/power fold/puddle lights) Limited Grill Mod Automatic Climate Controls Mod Automatic Headlamp Mod Sequoia Front Sway Bar Mod Sequoia Transfer Case Mod Sequoia Leather Steering Wheel Mod Sequoia Limited Gage Cluster Mod Sequoia LED Headlamp Upgrade Window Tint Fake Manual Transmission Mod 10" BAMufflers Stainless Catback Engine Block Heater Illuminated Ignition Key Ring Mod Deck Rail System w/cleats
    It could be as simple as an exhaust leak the the vicinity of one of the sensors and they're reading too much O2 in the stream. It might require two people, but with the engine idling cover the tailpipe with gloved hands and a towel or rag and listen for the little puffing sounds around connections....worth a try and is free.
     
    kenomouth64 and F1reheart [OP] like this.
  4. Aug 31, 2017 at 7:43 AM
    #4
    F1reheart

    F1reheart [OP] Love my Tundra

    Joined:
    Aug 17, 2017
    Member:
    #9112
    Messages:
    14
    Gender:
    Female
    Vehicle:
    2003 SR5 4.7
    Thanks! I will try the tailpipe option this weekend and report back.
     
    kenomouth64 likes this.

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