Nissan Repair: Pathfinder Acceleration Loss/Sputter, oxygen sensor, pressure and volume

Question
I am experiencing a loss of acceleration primarily when traveling between 60-70 mph but it also does it some times when i first start it up and take off.It dose this intermittently when it dose it it will do it for two or three days and then be ok for several days then do it again.I have replaced the fuel filter and it ran ok for about a week.I have had a diagnostics done on it and it says that the passenger side oxygen sensor is bad (running to lean) I have replaced it twice and both times it ran ok for about two weeks.What could be causing this problem?

Answer
Hi Steve -

This sounds like the fuel pump to me. Because it is intermittent, this is hard to diagnose with a fuel pump tester. However it does not hurt to check the fuel pump pressure and volume.

The fuel pump is located in the fuel tank.

Hope this helps -
aloha
calvin