I just purchased a 1992 MB 300SL for my wife. The car is in excellent body and interior condition. While at the dealership the car had no noticiable problems but, on the two hour drive home I thought I saw a "puff" of smoke in the rear view mirror. The next day I started the car and sure enough it was not smoke but small carbon particals being blowen out of the exhaust. I have done a oil change, changed all of the spark plugs (The old ones were fouled with carbon) and have added fuel injection cleaner but the problem does not seem to be going away. I am thinking that the car may be running to lean and if so how do I adjust it? When the car is sitting you do not see any carbon coming out until you rev it and then it does not want to rev until it clears a large amount of carbon out of it. My wife compairs it to our cat having hairballs. Any advice as to what to look for would be appreciated.