i have a 2006 gmc 2500hd and i need help figuring out what exactly is going on with my truck. my check engine light keeps popping up with the code p0174 sys too lean (bank 2) and i know that has to with the fuel and air ratio and what not so i did a few things and changed my air intake with the mass air flow sensor, the thottle body, the intake manifold, and all the sensers are basically new. i even changed my coil packs, spark plug wires, spark plugs, and O2 sensors. but still this code of p0174 wont go away. there were a lot of other codes to begin (6) with but those all went away, thats why i had to replace so many parts but this code is killing me. need some help...

 

​​​​​​​MAF related somehow. Check for unmetered air...vacuum leak maybe?

 

Ive checked all the vacuum lines and they all seem new so it doesnt seem to be a vacuum leak. And the MAF is brand new so im not sure what else to check.