1990 fullsize bronco 5.8 there seems to be oil coming thru the hoses and into the air filter box, why is this and what can i do to fix it. It has 134,000 miles I just did a complete tune up, plugs ,wires, cap, rotor, fuel filter, oil filter new oil, tranny filter , new fluids and a new cat back exhaust. it runs pretty good, but it still is a little rough at sometimes. What can i do about the oil.???? Thank you .