The code p0171 came up when i did a diagnostic test what does this mean?

Question

So i went to a shop and they put it on one of those real good diagnostic machines and they told me that it was the mass air flow sensor and theyrecommended a fuel injector cleaner and spark plugs but when i took it to a different shop and they did there tests they said it was my o2 sensors.. Well i replaced the mass air flow sensor but my check engine light is still on and the same code is still popping up what am i doing wrong

Answer 1

HI there,

This is a lean fuel trim code. The O2 sensors can cause it, the mass air flow sensor can cause it also. Vacuum leaks or a leaking exhaust system can also be culprits. Basically it sounds like the shop that said it was the O2 sensors may be the one that was right.