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420A P0172 Can't resolve it.

Posted by Red97GS, Jul 14, 2019

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  1. Red97GS

    Red97GS Probationary Member

    Joined Jul 13, 2019
    Prattville, Alabama
    Been fighting a rich condition for a year and can't find the cause. Mods: cai, egr delete, cat delete, oil catch can. 270,000 miles . Compression test done twice to verify 200 205 205 200. With the vss (manual trans)exception; all sensors fairly new and all pigtails checked. Ecu replaced. Fuel filter and for replaced. Pressure 50 psi at the rail. Anyone have an idea what I am missing? Fuel trims running negative 20 on ltft and negative 3 at idle. They get better with accel and cruise. Smoke test showed no intake leaks. Injectors recently replaced with no change in problem. Origional owner. Thanks

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