Have a P0305.Replace plugs,wires,coil.still getting misfire #5. What else can it on 2001 Mercury Sable

It only happens when the car is still and idiling. the engine light will flash and go away. When driving the car it is okay.

Asked by for the 2001 Mercury Sable
The same thing happened to my 2001 sable same code same same cylinder. The fuel injector is bad replace and the problem will go away.