my corsa b 1.2 16v stalls alot when cold ?

my corsa b 1.2 16v seems to stall alot when cold , but start second time and is fine , has anyone else had this problem, before it would cut out and not start for ten minutes,but since we changed the crank sensor,cam sensor,air flow meter,spark plugs and ignition coil,it runs like a rocket , but its just this little fault now ,has anyone got a cluie what it could be