A weak coil may fail under high loads, and work ok at light loads like at idle or cruising speed with small throttle openings. At high loads, it takes more power to make a good spark jump.
Maybe a shop could check the coil packs for you with an oscilloscope.
If you had an ECM problem, I would expect to see more codes pop up. What you see are common symptoms for failing coil packs. Your problem is identifying which one is the culprit.
if you drive with this condition too long, unburnt fuel going through the engine and into the exhaust will eventually ruin the catalytic converter. That makes it risky to try and actually drive it with a plug wire disconnected.
One coil pack seems to run around $80 at Autozone, just as one example. Maybe you could buy one, and replace a coil pack in your engine one at a time to see which one was weak. Could be more than one, of course. The P0300 means multiple random misfires. if it was consistently just one cylinder, the last number of the code would indicate which one. Since you have a 300, it means it's at least 2 cylinders. Since one coil seems to run two cylinders in your engine, I think it's a good chance that's what's going on.
ASE Master Tech
20 years of automotive repair & modification, USA, Asian, Euro, old & new cars.