2008 Audi s6 v10 P0355 Ignition Coil "E" Primary/ Secondary Circuit

Replaced all coils, spark plugs, cleaned fuel injectors. I have a misfire. Its pretty bad on cold start but once its warmed up it runs better. p0355 means cylinder 5. so i replaced that same coil twice( thought the coil was possibly a dud) but problem still persists. Oh and BTW I can start my car without pressing the brake pedal and turning the key. and the dome lights flicker alittle bit while car is running. where the heck is my misfire coming from?