Vy supercharged Holden commodore fires but won't start

car tries to fire but won't start I have replaced plugs coil packs ignighter spark plugs fuel pump crank and cam sensors tried a airflow meter off a running car when car fires it sometimes runs for a couple of seconds but very rough almost like timing is out if I spray either down intake it runs smoothe for five to ten seconds at my wits end don't know what else to try Iv had it scanned but no faults come up thank you so much if u can help