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Thread: Gen 4 4.8 with cats cut off started drinking gas. Guy has asked me to lean it out

  1. #1
    Potential Tuner
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    Gen 4 4.8 with cats cut off started drinking gas. Guy has asked me to lean it out

    So ive played with gen 3 stuff, and i think i have a general understanding of what it all does, but gen 4 im not sure about, i just need to get it to not burn super rich, not sure if its something to do with downstream o2 or the catalyst over temp protection, any input would help

  2. #2
    Senior Tuner
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    Dec 2019
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    What does the oxygen sensor data show?
    They dont automatically start running rich unless the oxygen sensors tell it to or there is an exhaust leak or virtual flex fuel is incorrect.

    Whats all done to the truck and where is the tune and a datalog?

  3. #3
    Senior Tuner
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    And does cats cut off mean basically open headers?

  4. #4
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    all i know right now before heading to it is that he gutted cats and added a thrush muffler

  5. #5
    Tuning Addict edcmat-l1's Avatar
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    businessman-looking-into-crystal-ball.jpg

    Might wanna take this with you, based on the information provided.

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