The pipe between the tb and Maf, right? I'm thinking this isn't oil, perse, but carbon build up. Same color as semi-old to old oil, but it's carbon build up.
If you pull off your tb, you'll be able to look inside and see a similar buildup in there. Do not pour carbon cleaner in there to clean it out. Soak a rag and run it in there, several times, until it all gets swabbed out.
I only think I'm right, but it's worth checking out.
Like Gib said, there is a hose that runs from the VC to the intake tract, and she will spit a samll amount of oil in there. You can always take the hose of and plug the intake hole and run a baby K&N off the VC.