i have a 99 EM1, and i have the idle surging problem thats like a little two step, and i was making sure the TB was fully closing and i saw that it appeared to be black and wet on the inside of the Manifold. i tried to stick a rag in to get a sample of it from what i got it smells like oil. is there anyway this could happen, if so why? could it be the PCV malfunctioning? i have a CEL for the IACV, i replaced it and reset the ECU and still the CEL keeps coming back on for the IAVC.

any info would help.
Thanks!