I am due tomorrow to take my car to the dealer. This is my 3th injector failure on the same cylinder.
I now think it could be carbon or it could be a software issue with the DDE mixture adaptation after the last update. Twice, the SES did turn ON after a long trip on the highway (~200 miles, 37 mpg) and with some idle hesitations. Three to four days later, driving in the city (25 mpg) with spirited driving, the SES light did turn itself OFF and the idle hesitations are gone.
Either, the spirited driving clear up the carbon in the intake or the mixture adaptation after driving in the city clear the problem.