94 Altima hesitation and oil leak

[Sukairain R-33]

So a friend of mine has a 94 altima with lots of miles on it >170,000mi. Not only does it have a strange clicking noise under the valve cover (with no effect on drivability) but now it's got the strangest oil leak i've ever seen:

The oil is collecting at the bottom of the spark plug insulator. When I stab the accelerator it bogs. If i apply the loud pedal slowly it revs normally.

The problem & symptoms don't jive. The oil leak doesn't make any sense to me. Someone help me out here i'm baffled.

[9240sx]

That oil leak is caused by a bad valve cover gasket,There's a few of them under there..(Around the spark plugs,around the side of the head,and around all the mounting studs..And the clicking is going to be the timing chain guide..You can just remove it..