black wet spark plugs

Okay I own a Procharged P1-X e85 2018 Mustang GT. Currently took out all spark plugs since I noticed I was burning oil. Cylinder 7 and 8 were blackened and you could see oil on it and the rest were normal. When I noticed it driving I didn't whomp on it at all just drove it normal and it acted...

I have a rebuilt '87 mustang 5.0. The plugs will be black and wet within 1 minute, then the engine runs ruff and black smoke. Idle bypass, egr, and coil are all new. ????