Results are inconclusive.
Move spark plug from 5 to another cylinder. While both plugs are out, compare them.
If its misfiring on cyl 5 and it has compression the only thing is spark. Now,a test for vacuum leak near cyl 5 intake port using brake cleaner would reveal a intake leak.
Coolant into cylinder is improbable,as cylinder pressure would pressurize cooling system.
Broken ring? Compression test says no.
18436572,
6,5,7 are 3 possibilities,crossfiring
To next firing cylinder through cap or jumping across wires.
Air fuel and spark. If its all there it shouldnt be missing.
Leakdown test,dont know if you will find anything.
