I was driving fairly quickly through town and turned on my road to go home when I the boxster started smoking suddenly from the tailpipe and I don't mean just a little smoke. It looked like a special effects type fog machine but when I let up on the throttle a little the smoke all but stops. There is some oil residue in the tailpipe but I took the air filter out and the airbox is dry. Anyone have an idea what might have happened? The car still idles good, runs and accelerates good but it was squealing like a belt squeal at low rpm after driving it about a mile.
Help!