Mick Sri 150

Hi hoping for a bit of help I'm currently driving a 2007 Vectra Sri 2.2 direct at the mome my it has developed a bit of a running issue. Starts OK revs to 3k just over clear and fine but soon as it hits 3k it pops and splutters almost like a miss fire on 1 of the cylinders if u back of the throttle and feather it gently it will rev. Kinda lost and don't have a clue what to do or where to turn. I am a mechanic by trade but haven't had much to do with these 2.2 petrol engine any help would be kindly appreciated, guess I'm kinda hoping someone have experienced this issue before... hope to hear from someone thanks for taking the time to read...