corsa redtop not starting

[sheldon0160]

hi everyone i am new to this forum.

I have recently had a problem with my corsa redtop.
it was going fine fine till last friday i installed my subs and when i put the terminals back on the battery went to start the car and it would try and turn over but jus wont start. i have tried diconnecting the sub and still the same, i have checked the fuses there fine too. i have a spark and i have fuel comeing into the engine but it just dont want to start. it sometimes does start (very rarely twice in 4 days) and it start fireing on 3 cylinders (cylinder 1 not sparking) yet when the car is not running it is sparking fine on cylinder 1.but stopes when the car did start. there was a alot of white smoke when it did start. the car ran fine before no problems what so ever. i had it pressure tested today and all 4 are normal.
someone please help as i do not know what else it could be.
thanks

[jordyp]

coil pack? only thing i can think of off the top of my head,