Coil Arcing/sparking

[5mudge 1]

Hi, just started my car after a while of standing still. Just changed spark plugs. Started up and it sounds like it's missing so with the engine running I removed a spark plug lead(any) and I noticed it arcs at the coil when a spark plug lead is removed.

Do I need a new coil or it a grounding/wiring issue?

 

Thanks in advance

[oldkiteman 6]

I wouldnt replace coil if it doesnt arc when the lead is connected.Its not unusual for the coil to arc out when a lead is pulled of as it makes the coil produce maximum voltage and its got nowhere to go.to check which cylinder is missing,pull off each lead in turn and short it to earth.watch you dont get a belt.