P0171 p0174 bmw 325i 2004

Question

Fuel pump new, and sparkplugs, new coil and new filter gas. I need help please

Answer 1

HI there

When you have the lean fuel mix codes on both banks of the engine it is usually the result of a bad mass air flow sensor. If it's reporting the wrong amount of air coming into the system then the computer will add the wrong amount of fuel. Then the O2 sensors see the lean mixture and set the code. Fuel pump can be a cause as well as issues with intake vacuum leaks after the maf sensor, but generally when it's affecting both banks like this and it's not the fuel pump, the maf sensor is the culprit.

Comments

Thank you, clean the code