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Z31 runs better when cold

  • spddemon
    spddemon
    Junior Member
    • 2
    #1

    Z31 runs better when cold

    Greetings everyone. First post here. I bought a 86' 300ZX about 3 months ago. It's pretty clean and a joy to drive. One issue I'm having though is it seems to be under powered after warming up. O2 sensor? Airflow problem? Any insight would be appreciated. Thanks
  • amreboot
    amreboot
    Banned
    • 9875
    #2
    Sounds like the O2 itself might be bad.
    Try unplugging it and see if the car drives any better. Doing this will causing the car to run rich, but thats okay for troubleshooting purposes.

    In fact, alot of us here don't even use the O2 anymore. I don't.
  • spddemon
    spddemon
    Junior Member
    • 2
    #3
    So all I have to do is disconnect the wire by the hood release? I'll give it a shot. Thanks
  • Butter
    Butter
    Senior Member
    • 1519
    #4
    O2=sensor going into your exhaust
    Unhook it's connector.
    The wire by the hood release is the sensor light wire, and should be unplugged already.
    sigpic
  • joselito76
    joselito76
    Junior Member
    • 27
    #5
    so I just disconnect the O2 sensor and keep driving for good?
  • DeleriousZ
    DeleriousZ
    Senior Member
    • 6874
    #6
    If you disconnect the sensor and the issue goes away, you know your 02 sensor is bad and needs replacing.

    You can also try running the ecu codes, it will tell you if something is malfunctioning.

    1988 300zxt. gt35, stance, etc. Wheels: Varrstoen ES2 18x9.5 et-13 225/40. 18x10.5 et0 245/40
    1990 jetta vr6'd
  • Kimbro Slice
    Kimbro Slice
    Senior Member
    • 1561
    #7
    If it's not the O2 then check your CHTS


    2001 Mazda Miata LS
    also a 1989 Nissan 240SX

    50th AE Build Thread SOLD 2015