Car was running fine and all of a sudden one day it started having problems starting. Once I had it started it ran great for about 3 days. Now it's having problems starting and stalls when I slow down. I had the egr and pcv valve changed and also have new spark plugs. The old spark plugs where black. The next part that we are changing is the fuel pressure regulator because we just noticed fuel is leaking out of the top when the hose is taken off of the top. Could the fuel pressure regulator be the cause of my car problems.