P0171 Chevrolet -

Question

Can you please help me?  I dont know what it could be.  I had both of my o2 sensors changed.  but the check engine light continues to aluminate.   My car runs pretty good.  it dos'nt stall or anything like that.  Its a very smooth ride.

Thank you in advance.

Barbara Ann

Answer 1

HI Barbara,

in most cases the mass air flow sensor will cause this code if it's not the O2 sensors. If the mass air flow sensor is reading wrong, then the fuel mixture will be off and cause the code. You really need a scan tool and knowledge of the sensor parameters to know if it's the cause or not. Basically you will also need to check for intake manifold leaks as well. These will cause the lean mixture codes too.