P0171 2000 Nissan Sentra / Datsun fuel system lean bank 1

Question

I bought Nissan sentra 2000 last year, and since that the engine light is come on. I went to the Auto zone, they told me po171 fuel lean bank 1.so I changed the oxygen sensor. But the light is not off. I went to the Nissan dealer and the told me to change the fuel pump and I did the whole assembly. After 55 mile the engine light come on. So what shal I do to fix this problem?

Answer 1

Hi there,

If there aren't any intake manifold vacuum leaks then I would replace the mass air flow sensor. If it's reading wrong you will get a lean fuel mixture and a lean fuel mixture code.