Volvo: renault espace v6 1996 model (automatic ), fuel pressure regulator, neutral safety switch

Question
my car had a problem with the reverse gear, sometimes it get into reverse and sometimes not, now after sending it for gearbox repair, sometimes it starts and sometimes not, when it starts it misfires and behaves as if its not getting enough fuel at the injectors, we have replaced the fuel pump and the fuel pressure regulator with new ones still the problem persists. what do you think is the problem because the mechanic has been trying everything for the past six months now.

Answer
Absolom,
I know nothing about the Renault, However is seems like the problem occures just after the repairs, so go back over the repairs maybe a wire harness was pinched. If the engine will not even crank while in park or neutral the neutral safety switch is not adjusted correctly.