rb30ets run an afm do they not? i would be ckecking that to begin with or at lest the conectons, cant remember if they are a hot wire afm or what ever they are called, and are they not also elec dissy?
also, this will be zero help as i cant remember exactly what i replaced on this, but my douche bag brother has a rb20e, that did the exact same thing, had fuel to fuel rail, had spark but very very week
long story short
it was one of the fuel/injector opening relays was sticking, not doing its job
fantastic cars mate had a ex ozzy police interceptor vl, was rapid fast
hope that helps in some way