I am having problems with the driver side door of my Citroen Saxo. It
intermittently takes excessive force to close seeming to just bounce
off the striker catch. The latch in the door seems to be in the
correct position and the door lines up and seems not to have dropped.
I have lubricated the lock and the mechanism and applied some grease
to the striker. The really strange thing is the colder the weather the
worse it is when the car is frosty it is impossible to close the door
from the inside. My mate is a mechanic and asked him to check it out
Sods law it worked fine closing 20 times plus with no problem.

Any ideas ?