vectra b fuel?

vectra z1.8xe engine misfires on idle/wont take throttle
sometimes it will suddenly rev up but still seems to have slight misfire engine revs drop&will either stall or
idle very rough back fire&knocks as in pre ignition
have replaced camshaft crankshaft sensors also throttle body
have changed fuel pump ignition pack air flow meter with another car(which run witrh my parts>