Codes PO 475 & 476 no power runs really rough.

Question

Check engine light came on the truck lost power and runs really rough. Codes PO 475 & 6

Answer 1

P0475 Exhaust pressure control valve malfunction

P0476 Exhaust pressure control valve malfnction

This code does not cause the vehicle to run rough , what this code is for is the exhaust back pressure regulator that control exhaust back pressure during cold ambient temperature , This code usually show when there is warm ambient temperature and you perform a KOER (Key On Engine Running) test. This is only a possibility that the exhaust pressure control valve is truly making the engine run rough and loose power or it is  a result of a rough running condition.