P0174 and P0171 code diagnosed for Toyota Harrier engine 2AZ-FE

Question

I have just replaced both oxygen sensors after check engine light is lit while driving. I am experiencing lack of power and prior to changing my sensors my engine did have difficulty starting at times. I have also replaced my spark plugs.

Answer 1

Hi there,

These codes are for a lean fuel mixture, both bank 1 and 2. This can be the result of low fuel pressure, and intake manifold vacuum leak or a problem with the mass air flow sensor.