While looking for oil leaks, I noticed some coming from the bottom of the intake manifold. After pulling the air filter I was amazed at the amount of oily grease on the intake manifold. Inside the manifold was a lot of carbon build up. I bought the car almost 2 years ago and had it looked over by a mechanic that I trust and respect. He told me the engine and tranny were good and strong. Neither has given me any real problems but after seeing this I'm concerned. The pics of the manifold are attached. Here are my questions:
Is this amount of build up and oil normal? ( I doubt it. )
What could be the cause? (Possibly intake valves way too tight and not closing properly?)
Will a valve adjustment remedy the problem?
Can I/should I pull the manifold and clean it?

Oh, mileage is around 160K (odo stopped at 120K before I bought it).

Attached Thumbnails