Hi John,
might be worth checking your HT leads to ensure that there's no oil in the spark plug wells ... a misfire throughout the rev range can also be caused by a faulty DIS pack ... which would generally not produce an error code ....
EDIT: just read your other post ... hmmm sounds very familiar!
had this on my first omega ... a slight misfiring, mainly noticeable at idle. Vx said there was nothing wrong. Following advice on here I pulled the HT leads, cam cover gaskets had gone on both sides - spark plug wells full of oil. Not knowing any better and being a bit of a omega newbie I then paid for an independent mechanic to fit new cam covers and gaskets - and I supplied him with a set of magnecor HT leads.
The pattern of failure (if left long enough) goes ... blocked breathers -> cam cover gaskets fail -> oil in spark plug wells -> HT leads fail due to being soaked in hot oil -> DIS pack failure
... it depends on what else is thrown up by the paper clip test ... but bear in mind that if this is what's happened, if the breather system was kept clear they the pressure wouldn't build up in the first place ... you live and learn!!!
