That's interesting. Do you think it's caused by some sort of buildup? How's performance? I'd think you'd have running issues and misfires all the time, since the compression stroke would be very poor at that cylinder. My misfire occurs only when starting up in the morning and letting the car idle for about 2-5 minutes.
I replaced my VANOS seals last weekend, but that's the only part of my list that I've gotten to since I first noticed the misfire problem. I still get a misfire code if I let the car sit at idle to warm up. Fortunately I got rid of my cold idle 'dips', so I'm ruling out the VANOS causing the misfire.
I don't receive a misfire code if I drive right off in the morning, and otherwise both cold and warm performance is very good. How do your symptoms compare?
I do think I hear some valvetrain noise, but when I had the valve cover off, I didn't notice more than what I'd consider normal amounts of varnish on the sides of the head. There was one spot on top of the intake cam oil splash guide with some sticky residue on it, but I imagine that's similar to what builds up on the oil fill neck.
I haven't run a compression test. I was planing to add another half bottle of Rislone for the valve chatter (it seems to help a little.. going try to be more scientific this time) then do the PCV valve next based on what I saw on the inside of the breather tube where it meets the valve cover.
Please follow up with more description of your symptoms and what you've come up with.