Plug 6 is generally the one that gets missed 
A toasted bannock says that the sponge on the firewall is completely soaked and dripping onto the coil pack plug...
My 3.2 had a misfire this evening. It's been pissingbrain for days. . No engine management light, but when I put the code reader misfire on cylinder 6.
It was okay later, after 5 miles of running, but i reckon it's water on the coil pack or the plug hole full of oily mayo.
When it stops raining I shall investigate.
It stopped raining. The more often I take the plugs put the easier it gets each time. I've had the car for 60k and I've had the coil packs off at least 8 times.
The cam cover gasket was done by me, about 50k ago.
The fault appears to be either:
have been the spring that sits at the end of the coil pack and wraps around the spark plug had come off the coil pack.
Damp.
A small amount of FOD in the plug well. (The remains of an oily rubber glove Which was probably me)
I swapped the spring for the one on plug 2, and swapped spark plugs 4 and 6. Thus if I get a misfire from 2, it's the spring, and 4 it's the plug.
Cleaned the plug well with erm cleaner and a cloth.
Put it all back together, deleted the fault code and went for a drive..
Seems fixed.