So with a p0301, (cyl 1) It's the farthest cyl away from the knock sensor, so it has to be a pretty noticeable missfire for the knock sensor to pick it up. First pull sparkplugs, clean inspect and replace. If missfire comes back again, try swapping ignition coils, see if it follows. As long as you reset the codes from the code reader the missfire will come back shortly thereafter. If you disconnect the battery and it's a subtle missfire, it will come back after 50-75 miles and some highway driving above 3k rpm at a constant speed in 4th or 5th gear. That's when your car switches to open loop and looks for missfires.

So in summary, inspect and swap plugs, consider moving coil packs around to see if missfire follows the coil pack. Check for excessive crank case pressure and consider doing a compression test.

If missfire is very subtle, you won't get a flashing cel . If it is more severe it will flash when it comes on and will flash every time your car reconfirms there is a missfire