I was idling my M50 last night to let it warm up and flow some gas because it's been sitting too long. Once it warmed up I could hear a small crackling sound. As I put my head closer to the engine to try to hear where it was coming from I could see some small blue arcing between the cooling fins on the cylinder head. It was jumping from the spark plug boot cover to the fins. I could see it because it was dark. It was doing it on both plugs (both front and back cylinder heads). What does this mean? Bad plugs? Bad spark plug wires? Bad ignition coil? Any help is appreciated.
(I've googled searched this and searched the forum for this issue with "arcing, spark plug, spark plug wires" and couldn't find any existing posts.)