Hey guys i have a 2016 c63s and one day i started the car and it was running a bit rough so i read the codes and got a cylinder 7 misfire cleared it and changed coil pack and spark plugs and still getting cylinder 7 misfire but now it also has cylinders 6 and 8 misfiring too. I swapped a working coil pack and with those cylinders and the code still remained and car drives and idles very rough. Eventually another code popped up along with the rest P0505 idle air control system. I'm just at a loss i dropped the car off to the shop to see what they say but any help would be much appreciated if you have been through this problem before or a similar one. Car has a tune and rear muffler delete only nothing else i loaded the stock tune on and had no change at all. Here is a picture of codes below.

You ruled out the problem being related to the ignition system, so it's probably a bad injector or an issue with the evap canisters (I think that's what it's called).