my father has a 1999 f-250 build date 11/98 4x4 7.3l psd. truck acts like its running out of fuel. sometimes it will run great then it will almost not run at. driving up hills truck loses power acts like its running out of fuel. loses all power on the highway at speeds above 60 it will began to run very rough till it loses all power. if u let it sit and idle for 5-10 min it will began to gain power again. trying to tow anything Is impossible as it will looses all power under any load. so far weve replaced fuel pumps, cleaned out tank and lines. replaced fuel filter. still no change. could it be the fuel pressure regulator? any ideas would be great as we don't know were to turn at this point and don't wanna keep throwing parts at it.

 

I am having the exact same problem. What have you found out to be the fix?