Oil on spark plugs

I have a 91 corolla 4 cylinder with oil on spark plug number 3. I ran a compression test and came up 165,155,175,175. The oil covers the side of the spark plug that actually sparks. The boot and wire was pretty clean. What do I do now? What can this be?

Are you sure it's oil and not unburned fuel/carbon? Have you checked for spark on that cylinder? Is the car using oil, or just running roughly?

-Rod

The oil is low and when I start it, there is a heavy release of exhuast. A blue-ish or grey color. It smells like oil on the spark plug. Just guessing but I'm assuming the tube that the spark plug is in, isn't sealing. Which would make sense why the rest aren't that way.

If the seal in the "the tube that the spark plug is in" isn't sealing, that oil should not be getting in the combustion chamber. The seat of the spark plug and threads would keep the oil out of the combustion chamber if the plug is properly installed. In this scenario the spark plug wire boot would likely have oil on it as well since I suspect the wires on your car are the style that have to go down a deep plug well and then seal to the valve cover.

A puff of blue exhaust on startup often indicates a valve stem seal that is leaking. When the engine is off, oil pools inside the head around the valve stem seal. The bad seal will allow oil to seep past it and puddle at the valve seat (valve closed) or on top of the piston. Then when you start the car, that puddle of oil will burn and cause the puff of bluish smoke on start up. Gray smoke is often indicative of an exhaust mixture rich in fuel.

We're getting some conflicting info from you here, can you elaborate?

-Rod