Engine hesitates at high RPM, 2005 3.7L

Discussion in 'KJ General Discussion' started by Tarkhan, Jul 4, 2020.

  1. Tarkhan

    Tarkhan New Member

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    Hello,

    The engine works just fine at low RPM but when it accelerates and reaches higher RPM, it starts to hesitate. The computer reads P0157 and P0158. any idea what can it be?

    Edit:

    This is what happens (notice the sound)
     
    Last edited: Jul 4, 2020
  2. 03GoingStrong

    03GoingStrong Full Access Member

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    If O2 sensor wiring and connectors are good ...

     
    Last edited: Jul 4, 2020
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  3. Tarkhan

    Tarkhan New Member

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    So is the hesitation related to the error codes?
     
  4. 03GoingStrong

    03GoingStrong Full Access Member

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    If the fuel air mixture isn't right, the engine will not run properly. First, I'd check for frayed and worn wiring such as the guy in the video talks about the O2 sensor wiring near the driveline, but follow the wiring and check connectors too. Rule out the simple stuff first.

    EDIT: Check these links for some ideas ... https://repairpal.com/obd-ii-code-p0157 ... https://repairpal.com/obd-ii-code-p0158
     
    Last edited: Jul 4, 2020
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  5. Tarkhan

    Tarkhan New Member

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    This is what happens (notice the sound)
     
  6. LibertyTC

    LibertyTC Well-Known Member Staff Member Moderator

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    P0157 2/2 O2 Sensor Shorted to Ground
    P0158 2/2 O2 Sensor Shorted to Voltage
    Sound like wiring issue or bad sensor.
    Only use NGK/NTK 02 sensors for the replacements.
     
  7. Tarkhan

    Tarkhan New Member

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    Thank you. Can that be the reason why I'm having this hesitation?
     
  8. LibertyTC

    LibertyTC Well-Known Member Staff Member Moderator

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    Yes.
     
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  9. DadOSix

    DadOSix Full Access Member

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  10. 03GoingStrong

    03GoingStrong Full Access Member

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    So very true. I'd forgotten about that. Don't often redline the engine LOL and was so focused on the codes, didn't pay attention to detail in the video. Wonder if the codes are a result of redline or preexisted? Clear the codes and see if they come back I guess ... and don't redline the Jeep.
     
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  11. Tarkhan

    Tarkhan New Member

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    Thank you so much guys, I didn't know that tbh (that's my first Jeep). I will try to clear the codes first before checking the sensor.
     
  12. DadOSix

    DadOSix Full Access Member

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    Redline won’t set codes.

    i’ve got 2 - an 04 and 06

    both 3.7, both auto.

    from libertytc’s post, sounds like the wire has rubbed thru.

    good luck!
     
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