Sudden misfire and its not due to rain

[Bracechenko]

As soon as i have i mentioned that im going to sell my FZS600 it has developed a sudden misfire. I was having a hoot on it yesterday scrubbing in a new front tyre but i needed to fill up. So, engine off, buy some fuel but when i restart it, it's only running on 3 cylinders.

Plugs are new, all leads are checked and connected properly. I'm thinking that the coil pack has gone kaput maybe? How do i check these things and any other ideas?

Cheers
Brace