Rep Power: 0

Honda Civic 99 Si.

I have an aftermarket K&N air filter.

What are the causes for engine oil on my air filter and in the tube it attaches to?

I fear I'm screwed.

 
Rep Power: 174

So is there oil all over the inside or outside of your intake? Did you check the smaller PCV tube and the valve on the engine block it's connected to?

 
Rep Power: 0

The oil is on the inside of the air filter and exhaust tube that its connected to.

I took the air filter off to clean it and noticed.

No i have not checked the PCV tube or valve connected to it.
It didn't occur to me.

I just looked up what a PCV valve does.

What exactly am i checking for?
Why would this valve being broken cause oil in my air intake?

 
Rep Power: 174

The crank case is one of the key areas that are lubricated by engine oil. It's pretty unlikely that the oil would have come all the way up through the intake manifold and into your intake itself since the airflow would be going the other way. If oil is leaking into the valve then you may have a leak somewhere in the engine. That, or maybe there's too much oil in there or something. How much oil did you put in on your last oil change? When was it? How is your oil level looking now?

Whatever you do, make sure you clean the throttle body and intake out well. Can you take any pictures of the problem?