No fuel leaks but won't start!

[86ford7.3]

[1986 F350 XL Single Cab Dually, 7.3 IDI non-turbo, 5-spd man.]

My truck all of a sudden started idling really rough about a month ago, then didn't do it again till a few days ago, now it won't stay running longer than about 10-15 seconds

I replaced all the O-rings on the fuel injectors and a couple bad return lines... no leaks there; I even added a in-line electronic fuel pump made for diesel (by mr. gasket, bought from Advance Auto)

while i do suspect the lift pump is bad, the electronic pump is definitely sending fuel to the filter..

so no leaks and fuel is definitely getting to the engine...

any suggestions ???

 

['94IDITurbo7.3]

Sorry i can't help but ask this in the IDI section, much more activity.

 

[86ford7.3]

well, i kinda use my truck every day..... so needless to say i need my truck asap

(i figured that this emergency help thread thing would be the better place given my situation and need of my truck)