" I see that the code is a Cylinder 1 misfire. But what exactly is this? " It is exactly what it says. The # 1 cylinder has a misfire. this can be cause by a few different things.
1. Fouled or damaged spark plug 2. Failed spark plug wire 3. Failed coil pack 4. Failed fuel injector 5 .The " not likely " bent valve 6. Bad gas, but usually will misfire on all cylinders 7. Loss of compression ( loose plug, crack head, blown head gasket )
First thing is to remove the plug examine it, if the electrode is not rounded then place it in the wire, let it rest against the block and crank it over.. see if it sparking. This rules out the coil pack , plug and wire unless they are damaged and arching . Examine closely. If in doubt , replace them . Remember the problem is only in cylinder # 1. See if the fuel injector is firing. Check compression in relationship to # 2 cylinder. More than likely you just need a good healthy tune up. Go ahead , its probably been a while anyway. After that, treat it to a nice fresh tank of High Octane.