Not sure if this would have 2 different fuel filters, (one for each tank) but are all the equipted fuel filters new and clean? I belive that between then fuel pump and the sending units on those there is a rubber hose conecting the pump to the SU. Make sure that its not leaking or that it has a hole in it. Or that any possable rubber hoses in the system arn't kinked a little. Do both pumps also have new fuel strainers on them as well?
Hope this helps a little good luck!
Hope this helps a little good luck!