Checking the Duty Cycle while suspecting the fuel system isn’t very useful. The first thing that comes in to mind while facing this condition is that the system is leaking down pressure, it can be a leaky injector , a faulty cold start valve or even a leak inside the FD- keeping this in mind; starting with the basics such as a filter replacement is a must as it’s usually overdue for service and relatively cheap compared to the other components of the CIS E system.