Let me double check my FSM's, id look right now but my computer is oh so screwed up right now!!
http://www.phatg20.net/
You can download the hardbody FSM from there. You can double check what your fuel pressure at idle should be. generally on Nissan's its around 34ish PSI.. Im going to go ahead and say that your fuel pump is shot... Certainly fits right in... But i dont know until i know the base fuel pressure.....
Its also possible if your pump is good, maybe your FPR is bad... I dont know if those go bad on those cars, but its possible...... All the info you need is in the FSM..
Do some investigating in the FSM and let me know what you come up with.