I've heard of a lot of faulty cam positions sensors causing stalling and/or drivability issues on R51 Pathfinders at another site which I monitor and they don't always trigger trouble codes. Fuel pump failures are pretty rare and I would test the pressure before replacing the pump.
When these vehicles first started having problems with the ECM relay, Nissan was replacing the entire IPDM/ER because they said the relay was non-serviceable. Then, people figured out that they could replace the relay without replacing the entire IPDM and not long after Nissan smartened up and went from replacing the IPDM to just replacing the relay. Most if not all of the IPDM's they replaced were perfectly fine outside of just needing the one relay.
When these vehicles first started having problems with the ECM relay, Nissan was replacing the entire IPDM/ER because they said the relay was non-serviceable. Then, people figured out that they could replace the relay without replacing the entire IPDM and not long after Nissan smartened up and went from replacing the IPDM to just replacing the relay. Most if not all of the IPDM's they replaced were perfectly fine outside of just needing the one relay.