u/Bama-1988

I have a 2015 q60s with about 194k. Well maintained the entire time. Everything on time. About 5 months ago I drove it to work all good. Get in to come home rough idle power loss got it home. Started it next day rough idle, no power and smoke. Thought head gasket. Money tight I have other vehicles so I parked it. Today I was gonna finally try and diagnose so I could fix whatever it was to get it back on road. Well charged battery and started it up. Rough start up, then slowly idle down perfectly and smoke started clearing. No smoke, no rough idle and full power. Now I’m confused. Coolant looked good from what I could tell. Haven’t checked oil yet. Codes I could pull was P0300 and P0302. Something was stuck or faulty. Now I don’t know where to start other than cylinder 2. Anyone else have similar issue? Stuck injector? Coils and plugs.