codes P0171 & P0174 plush flashes EGR. Can find no vacum leaks.

Change the fuel filter soon to verify, could also be an MAF problem.

po401? most common problem= faulty dpfe sensor and clogged egr ports. po171,po174= collapsed/split pcv tube at rear of throttle body. not saying this is what your problem is,but I have made a very good living replacing these parts with no comebacks.