door latch problem

[hursty]

1990,c4,targa,r/h drive.
drivers door works almost perfectly except when opening from outside, the latch opens once but not enough to open the door completly, push the door towards closed position a little and trigger will then open door( sometimes) if not i can open the door from inside no problem,i have checked threads on this and found some good photo's of latch mechinism, have cleaned mechinism wd40 without removing from door (remove from door as a last resort ),all idea's greatfully recieved.
hursty