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

Well i replaced the number 5 coil and it still run like shit. Interior lights dim and flicker while it is running rough at idle (misfiring). I turn the car off and restart and its running better. I deleted the codes ( reset the CEL) problem came back and then EPC comes on and now it just sucks. CEL blinks off and on. Car is parked with bumper off (working on headlight). SO i cant drive it so the codes wont come back until later. I know what codes they are though because I wrote them all down. I heard it could be the injector but I just clean them all inside out with the carb cleaner injector cleaning kit( the can adapter and power harness that fires injector while spraying the carb cleaner). Gave them all a good cleaning. but maybe that one is faulty.

Anybody got any suggestions? BTW do yall think this could be a short circuit somewhere. maybe the ignition system?
IDK but I forgot to mention the car battery drains after everytime I recharge it. in maybe 2-3 days or less it is weak or dead again.

If your battery is not recharging, that sounds like a bad alternator. Also double check the ground on the alternator while you’re at it.

Has anyone replaced an alternator on one of these?

I just got quoted 6+ hours. Any idea how to swap one

You need to either remove the radiator, or put the whole front carrier in servide position. Then it’s pretty straightforward - taking the belt off, two bolts holding the alternator, one nut, one connector and two cooling lines.