brnt999

I recently bought an 1984 Bronco 11.I dont know much about mechanics.I was told a rebuilt motor was installed 15,000 miles ago and have no reason to doubt this as the block looks new.I assume it is the original motor--2.8l V6. I noticed that the engine idled very fast and my gas mileage was very poor.Yesterday I had the hood open and the engine running and I could hear a sucking sound. I traced it to a fitting on one valve cover where a larger hose is attached to the fitting and there is a second smaller hole on the fitting where a smaller hose should be attached. I put my finger over the hole and the sucking noise stopped and my idle dropped to normal.I looked for a hose that had become detached but couldnt find one.I taped shut the hole and drove the car last night and the differance is like night and day. The engine runs smoother, the idle is normal, and I have more power. I am assuming my gas mileage is better.My question is can anyone tell me where this missing hose is supposed to run too and if I can do any damage by taping shut the hole.
Thankyou