Car: Audi S5 4.2L V8 FSI
I have my intake manifold out to clean carbon of the intake ports. When I was removing the port separators, I noticed some were really dry (light grey carbon), others were dark black (but not shiny). But I noticed two (circled) were black and shiny and looked wet. Is this something to be concerned about?
It seems to me that the only source for the carbon build up would be the PCV valve or maybe leakage from the intake valves, but given that most of the time air is being pulled in, I'd bet on the PCV valve. I'm thinking that what you're seeing reflects that pattern of air flow from the PCV valve outlet to the cylinders.
The wetness could be condensate from the PCV system, depending on how the car got to its current location (was it short drive without time to warm up completely) the wetness could be an artifact of not getting up to full operating temperature.
