Your problem could be the drop in system pressure from a leak in the return line, but something tells me you've got more going on. Can you hear the in-tank pump running? I would double-check the fuel pump relay - try a known good one, or re-solder the one you have, for goodness. Fuel pump fuses OK? Don't forget the 25 amp fuse under the hood, between battery and coil. Also, with the engine NOT running, pull the vacuum line off the fuel pressure regulator and sniff for raw gas smell. If you get that, the FPR is shot and you need a new one. <=== just the basic stuff