p0171 code after replacing o2 sensor with oem sensor

Question

first the car gave me the CEL code for a bad o2 sensor (bank one)
after replacing it with the original factory replacemen the CEL light went away for 2 day, and now it came on again with the PO171 code, and the car have a rough idle to.

Answer 1

HI there,

This code means there is a lean fuel mixture on bank 1. It's not likely the sensor causing the issue if the engine is running rough. Look for intake vacuum leaks as a possible problem and low fuel pressure. Sometimes a faulty mass air flow sensor will also cause the problem as well.