Hi guys, I have a major missfire problem on my 2001 Impreza since a coil pack fell out of the head ( the one nearest the turbo ), I screwed it back in, thinking "few, glad it was something obvious" but problem percists, swaped coil packs but this didn't transfer it to other plug! took plug out but looked clean and was petrol free, which was odd!!!
I have run out of ideas and am now looking to this super knowledgable community, any ideas?

 

BTTT
Come on, someone must have an idea or two!!