I had to pull the head on my 02 Civic LX. I had a ck eng light for nbr 3 miss fire and found the plug a little brown and the other three clean. At first I though I had a valve seal leak but when I screwed in the air hose and pressurized the cylinder with the air compressor, I could hear a buble in the radiator reservoir about ever minute or two. The unusual thing I found is that when I pulled the intake, I found oil in a cavity of the intake mounting block. This engine has a plastic intake and an aluminum block that goes between the intake and the head. The inside of the intake had a slight oil film, but there is a cavity in that adapter block that was full of oil and I don't know how it got there unless the PCV valve is feeding oil to the intake.
The engine has 120,000 miles and had all it's oil changes. Plus, normally when you have oil feed from the PCV, it is an indication that your rings are shot. Typically with shot rings, you hook up the compressor to pressurize your cylinder and you can hear the air going by them into the crank case. My cylinders are tight as a whistle. Any ideas?
The only thing I'm wondering is if maybe the headgasket was allowing some of the pressure from the cylinders to blow through into the crankcase. If that is the case, I'll be fine with the new head gasket.

 

Since you did a leak down test, how much leakage were you getting? The number should be pretty low. Also, air bubbles in the coolant mean that your head gasket is leaking.

 

Leak down was so little that my 30 gal compressor didn't have to kick back in and run. Yeah, I pulled the head gasket. No visible damage there.

 

did you use a leak down tester to measure leakage? you should be able to determine the % leakage of each cylinder. your testing is inconclusive unless you have these numbers.

also, you probably won't see visible damage unless the head gasket is leaking badly...might want to check if your deck is warped too