P0171 / p0174 code

Question

Hello I have a 2004 Chevy suburban 5.3 . I just recently rebuilt the top end of the motor all new gaskets hoses and cleaned everything. Also have new oxygen sensor all 4 replaced. I put shorty headers on instead of exhaust manifold. Could this be giving me the p0171/0174 code problem? If so how do I correct it. I have no driveablity issues plenty of get up and go. Thanks for any information.

Answer 1

Installing short headers, create a P0171 and P0174 very unlikely, neither would the 02 sensor being installed cause this condition, For the engine to set a lean condition on both side of the engine, you need to have something that affects both side of the bank such as fuel pressure, MAF sensor not reporting correctly, a vacuum leak right after the MAF senor, a slightly open EGR valve, a fuel pressure regulator leaking fuel into the intake .

​ The most likely component that would set a lean condition for both Bank would be the MAF not reporting properly, Do a MAF cleaning, use brake cleaner.

​ A EGR that is slightly open would also be the cause for a lean code on both side of the Bank, If the EGR is hot to touch at idle, that indicates it is slightly open