[shab_xp]

Man, this is an oil-in-distributor problem. The oil will foul the optical sensor inside the distributor, and cause misfire.

Take the distributor off. Clean the oil inside the distributor. Pry the old o-ring off the shaft using a screwdriver, and replace it with a new one. When I changed mine, the only way to get the o-ring is from the dealer, and it was not in stock. So I just asked the auto shop to match one. It's 50 cents.

Be aware that you need to make sure not to mess up the ignition timing during the processes. Mark the position of the distributor relative to the engine, and the position of the distributor rotor relative to the distributor. Never turn the crankshaft or ignition key before you put back your distributor.

I also recommend you to change the distributor cap and rotor when you do this.

Good luck.