[pbs911]

How did you pull the plugs wires off? It is possible that you separated the core of the plug wire from the connector and it is no longer sending spark to the plug. Since the old plugs did not cause this "miss" did you try the old plugs again? If you did, and the miss is still present, I would bet the wires are crossed or you pulled on the plug wire, separating the connections.

I am also confused about your statement that "you can here it sparking when it's running - but couldn't see any!" Can you explain what this means.

Have a beer and go back and take a look. its the simple things that drive ya nuts.