P0171 Pontiac -

Question

I just replaced the mass air flow sensor and now the p0171 engine code came on what could be wrong? I have a 1999 Pontiac Bonneville

Answer 1

P0171 Fuel system lean bank 1

False air will always give a lean bank code, false air is when air enter the engine through disconnected vacuum line , rupture vacuum lines that gets past the MAF and interrupts the fuel to air balance, this also include low fuel pressure the fuel pressure .