Also, I would verify they you are getting enough fuel to the filter... with engine running, (not sure of the 94 does or not) but there is a Schrader valve that should have fuel coming out when pressed in (and running). If not you have a restriction feeding the fuel filter. Next check to verify that the filter isn't plugged (again)
Yes I read you changed your filter, but I've gotten slugs of garbage in fuel before, changed a filter, bleed it out only to find the new filter is plugged up too.
A quick and dirty way to see if the filter is restricting flow is again with the engine running, using pliers or vise grips, pinch the bypass hose on the filter housing and then pull it off the filter housing ... if fuel comes out its not restricted. Now rev the engine a little it should still flow steadily. If it does not, slows down, or stops all together.. your filter is plugged (assuming you checked that the supply if fuel to the filter is flowing well)
All else fails, check that the fuel return to the IP is NOT restricted. If it is, it will allow a truck to idle, but not anything more. The slightest restriction will have drastic consequences.
Good luck mate!