I have a '86 420 SEL that leaks oil out of the fill cap. I believe that there is too much pressure in the system. I have checked the pcv valve (or hole) and cleared it. I did notice one time the car burned excessive amounts of oil when it was first started and quit a short time later when it was warm. I haven't noticed it burning oil since. The car does have a rough start for the first few seconds and then smooths out. These are all of the symptoms and some or all of them may or may not be related.

Any thoughts?