You should try mounting your fuel pump a little closer to the tank, i run a bigport 4age with some dodgy efi pump out of god knows what and have not had a problem.
I also ran an 8mm line to the fuel rail for better flow and future mods, i would also reccomend this. A mate of mine with a gze used is original (6mm) lines and it ran like shit until he replaced them and it was sweet.