Roaring noise from air intake

I have a 96 Aerostar with 228,000 miles on it. It does the same thing. Mine is a howling noise at idle or in drive at a stop light. It comes from the idle air control valve located in the throttle body. It has two small bolts that hold it on, and an electrical connection. I take mine off every so often when my wife can't stand the noise anymore, clean it with carb cleaner and toothbrushes. From Autozone, the part no. Is AC473 and cost 42.99. Check and you might get a AAA or military discount. Autozone will also give you a free check on that check engine light, and give you a code to work with.