I would stay with cleaning with techron or equivalent. I had good success with Lucas injector cleaner. Wife's car started having similar creeping m random misfires. First just in on one cylinder, I swapped that coil then it just moved to a different cylinder. Swapped one more coil then I ran a bottle of injector cleaner through 1/2 a tank of fuel and haven't had a shaky start or engine code since (at least a month now).

__________________
2011 E70 • N55 (me)
2012 E70 • N63 (wife)