got a po171 code on ford v-10

Question

change fuel pump
changed o2 sensor passage side

Answer 1

P0171 Fuel trim lean Bank 1

any Exhaust leak right near the front 02 sensor, or exhaust valves noise at cold start up. these are hard working type engine. What you may want to try is a MAF sensor cleaning using brake cleaner . which is the cleaning solvent that Ford recommends. even though it set a lean code on one side.