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2003 Mitsubishi Eclipse 2.4l 4G64 - P0171 + readiness monitors will not set.

Posted by jazzie366, Aug 20, 2019

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  1. jazzie366

    jazzie366 Probationary Member

    Joined Aug 20, 2019
    mahwah, New Jersey
    Hello all, I have a the aforementioned 2003 Mitsubishi Eclipse. It will not pass any monitors when going through a drive cycle, and it will also throw the code P0171. I am a fully certified technician, and this thing is throwing me a curve ball. I have the P0171 narrowed down to a leaking throttle body, the seals on the blade shaft are leaking and the whole unit must be replaced. Now, as for the monitors not setting, this is new. I used to be able to drive it lightly and keep my foot out of it and it would pass inspection no problem. However, it's running really lean currently, even though the throttle body leak is minimal, and it runs lean at any throttle position. I have replaced the following to attempt at remedying this: Fuel pump, MAF sensor, MAP sensor, TPS sensor, and I have re-tubed the entire engine with new vacuum hosing to be sure. I also replaced the EGR and EGR solenoid. Still no luck, runs like garbage all the time, fuel trims are very high, usually +10% - +20% which is quite high and well above the 12% threshold to set the code. The car also lacks a lot of power. I cannot pinpoint the source of this and am at my wits end. Anyone have any advice for me? All is greatly appreciated, thanks.

    P.S. I am working with a Autel MaxiCom MK808 which is a 2-way diagnostic scan tool. I can test certain control systems.
  2. ThunderChild

    ThunderChild Supporting VIP

    Joined Jan 5, 2012
    Rathdrum, Idaho
    Have you checked/replaced the fuel filter? This sounds like classic clogged fuel flow, so filter/injectors...

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  3. mitsubishikid

    mitsubishikid Proven Member

    Joined Jun 8, 2009
    Turlock, California
    Did you try cleaning or replacing the o2 sensors yet they might be faulty also fix the throttlebody leak I have heard of the actual pipe style intakes on these models cracking loose under the throttle body on the 3g eclipses, and a lot of owners swap it for the cast outlander intake.

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