2003 Sentra 1.8 S Cranks several times before starting

I have several Nissan Sentras that are doing the same thing. At a cold start, or after its been sitting for a short period of time. When your going to start it the engine cranks several times before I think fuel goes into the injection system. I think it might be the fuel pressure regulator that might be leaking fuel out but cant find it on the fuel rail. Need Help