Thanks for the update. This model is known for injector failure issues. One very common condition is latching of the spool valve, or referred to by Ford as "Sticktion" which is an abbreviation for Static Friction. This condition is caused by oil accumulation on the ends of the spool valves, between the valve and control solenoid, there is a drain hole for this area but at low operating temperatures, oil will latch onto the valve as it is commanded to move and slow it's movement, causing a missed or late injection event, poor cold start and poor performance at low engine operating temperatures. as the spool valve and it's bore wear, the amount of oil which can accumulate in this area will increase and exacerbate the issue.
A certain amount of wear as injectors age is normal. extended service intervals and coolant contamination of the engine oil will both cause more rapid wear. coolant from failed EGR coolers has been proven to wipe out an entire set of injectors rapidly, not to mention the wear and damage it will cause to other components which require engine oil lubrication.
Ford sought a fix due to the high number of injector warranty replacements. the first attempt was to cycle the injector spool valves for a short period after engine shut down. the purpose was to purge any excess oil from this area, but this was found to be ineffective due to oil accumulation from leakage after a cold start up.
The next attempt was a developement of the inductive heating flash. this software applies a current to the close coil which creates a rapid heating of the coil and surrounding components which allows oil to drain away much faster, eliminating spool valve latching. Inductive heating solves nearly every case of cold start performance issues, and extends the service life of an injector.
Injector harness issues have been quite common. Chafing of the harness and eventual breakage of wires can cause drivability issues such as misfire and can set circuit DTC's in the PCM memory.