Individual Cylinder correction #3

[Maddog20]

I have been trying to nail down the cause of the spark plug in cylinder #3 appearing too rich. The porcelain is almost completely black except for right at the tip.The individuals cylinder trims where dialed in on the dyno along time ago, but as the software has changed my tune has had to change with it. Right now the settings for cylinder #3 are set at (2) for Fuel and (-1.00) for timing. My concern is when people have engine failures it usually fails at cylinder #3. I am unsure of the direction I should go? less Fuel or more timing? My A/F ratio seems good 14-15 at idle and light loads. 13.5 for the medium load and 11.5 in boost. The plugs in 1,2 and 4 look good maybe a little rich. Opinions?

[fr33w0rld]

umm..maybe u wont like my idea...valve stem is leaking in cylinder number 3...causing oil burn..enough to blacken your plug....