93 NA ATX 3000gt DOHC
Haven’t read all this thread but looking at the crimp in that hard line, I’d say that might not allow enough fuel for above 5000 rpms. Was that already there or did you do it trying to break fitting loose? Just to be sure you know the male connector on hard line is fixed (does not turn on hard line). You have to hold it steady and turn female connector/hose together. If you try to turn male connector, you’ll crimp hard line like you see in picture (restricting fuel flow).
You have to break hose loose under car front of tank first and rotate hose assembly to unscrew it from hard line male fitting to pump hat.