Supersedes Technical Service Bulletin Group 01 number 13-86 dated April 15, 2013. The MIL is on. There is a rough idle. DTCs are stored in the ECM. Engine may have reduced performance without significant loss of power or stalling. Because there are a number of different misfire faults (unrelated to ignition coil operation) that could cause the MIL to illuminate, proper Guided Fault Finding (GFF) misfire diagnosis must be followed before any ignition coils are replaced.