Ditto Rocky above...does it fire on the second cylinder at all...sometimes...never?
In situations like this, swaping comonents over often helps to identify the culprit or at least give you some pointers.
Try swapping over the HT leads (if they will reach?), coils, plugs...and give it another go.
Was this something that just started happening on it own or is it a result of an action on your behalf (i.e. riding in the wet ot summut??).