mn15

Thank you!!! Ended up being bad injectors.

2015 Sierra SLE 5.3L w/ 104k miles. I have been getting nonstop CEL codes for the past few months. After replacing all 4 O2 sensors, purge valve evap, PCV, thermostat and cat, all codes go away after I clear them only to reappear when I drive it next. Took it into a shop and they can find no vacuum leaks. Current codes are P0172 bank 1 too rich, P0175 bank 2 too rich, P0430 catalyst system efficiency below threshold bank 2. Truck drives fine most of the but rpms dip and at times it feels like there is a misfire, plugs were replaced at about 80k. Any help would be greatly appreciated. Thanks.