Hi Rock Nissan...I work at a nissan dealership and I've seen this before. There is actually a TSB on this (if you're getting a hard start/long cranking). The fuel pump on the sentras are weak and doesnt supply enough fuel pressure so replacing the fuel pump motor with the updated one will fix the problem.
Have you know the faulty fuel pump to cause the service engine light to go on for multiple cylindar failures. Once started and running. my sentra runs fine, but I haven't had a confident diagnosis of what is causing the service light code.