Have you checked the pressure at the injector pump? Needs to be 10 or better. Next have you attempted to bleed the lines at the injectors? Agree the factory lift pump is less than adequate but the pressure reading tells the story!
I haven't checked it yet. With a new lift pump and a fairly new filter I figured I must be getting enough pressure to the injector pump. I bled the fuel system after replacing the injector pump and again today after replacing the lift pump. I'll see if I have a pressure guage laying around that I can hook up to it long enough to check and then remove. My buddy has been telling me for years to install one.
