Haunted by P0171 & P0174 - Need help
07 GT with Airraid CAI, under-drive pulleys, short headers, stock h-pipe, Bama performance tune, new valve cover gaskets, new timing cover & gaskets, performance coil packs, straight pipe exhaust, Ford racing intake manifold. The car has been smoked tested many times, hence replacing gaskets and timing cover. 100% confirmed there are no more vacuum leaks. Pressure tested fuel pump & filter, they check fine. Both o2 sensors tested and fine. Highest reading from datalogging on sensors is 1.25, never below 1. Have replaced nearly every sensor yet no matter what, these codes will not go away. Have run a few tanks of 93 through it just to get it to burn cleaner but the CEL & codes always come back. Any thoughts on what else it could be?