fuel pressure sensor

2005 E450, 6.8 Had check engine lite come on, code was fuel pressure sensor, replaced, 25 mile later check engine lite on, code fuel pressure sensor again, mechanic replaced again, 100 mile later, check engine lite on again, code fuel pressure sensor again, This last time I was on my way on a trip and just keep going 600 mile as engine seemed to run fine.

Question is , Have I got 2 bad replacement sensors (mechanic gets his parts from NAPA) or is there something else that could cause the sensor to go bad.