ford ef xr6 misses when running on petrol idling and when taking off it studders a bit. thought it was the injectors just changed them with au ones but still missing. what else could it be?

coil pack, leads, plugs?

Welcome to the site mate.

Check the intake gasket. I'd bet you its probably cracked there somewhere. If not, next I'd say is a d**k lead thats one the way out (which probably comes good for you as you up the revs) that or a plug

AS above,check coil pack primary and secondary resistance,check spark plug lead resistance and make sure spark plugs are not dirty/fouled and that correct plug is fitted.While you have spark plugs removed,if you find that one is clean and shiny,this indicates a leaking head gasket.Also check for vacuum leaks,especially from intake manifold gasket.If you have a timing light,hook it up and check that base timing is stable at zero degrees in diagnostic mode.If there is excessive timing mark movement, or there is an intermittent miss which corresponds with the timing mark moving to right (retarding)intermittently,then this indicates a faulty camshaft position sensor.

cheers yeah im gonna check the leads and that when i get time. i took one spark plug out the other day there ment to be fairly new but there pretty dirty and were black? and i got the intake gasket changed not that long ago but still ran rough after i got it done thats why i wasnt keen on taking it back to the mechanic