I got this truck like a month ago. After I got it the evap code was on I took it in to the shop it was replaced but it wasn't plugged in so they hooked it up for me its still got a hard start. It takes 3 turns to get it to fire. I've replaced the fuel pressure regulator and plugs and wires and nothin. So now I got p0171 system too lean bank 1. I've clean the maf sensor and 3I days later it came back on

Anyone have this problem?

 

it might need a new sensor also you want to really look at the manifold if its cracked anywhere it will throw this code all day if its not really effecting anything you might also look at the 02 sensor it could just be going out

 

debo Welcome to the forum...

What year and engine do you have?
It might be worth checking the fuel pressure as well.... and as nkh34 suggested check for any vacuum leaks...

 

Need help have a p0171 code comes on only at night I clear the code and drive all day and Nothing it only comes on at night checked intake for leaks mass air clean new plugs wires cap rotor. What else can I do to make it go off

 

1999 k2500 suburban was throwing p0171 bank 1 lean codes. I chased vacuum leaks as main cause to no avail. Ended up pulling upper intake manifold and replaced fuel injection spider. Problem fixed and runs much better. Before was hard to start and ran rough at all rpm’s. Long term fuel trim was in mid 20s on bank 1. Replaced bad pre cat o2 sensor on bank 1. I waited on replacing the fuel injection because I didn’t have both p0171 and p0174 codes, but apparently only injectors on the left side were partially clogged.