vectra shutter when idle help

[tomsta79]

its about me vectra 1.8 petrol 51 reg its got a shutter on enigne when just sitting there ticking over.. looking for a bit help ive cleaned throttle body...but can not clean air control valve as mine is all in one and does not come off..but a lot of people are saying it is down to the dis/ coil pack and old plugs am going to change them to see if that works..hope so as its costing money all the time to find out the problem...any help would be great thanks