You make think this is a strange question, but: Does you car use oil without leaking or smoking?
My car does the exact thing and I believe we have it narrowed down to leaking valve seals.
I'll know for sure in a couple of weeks.
1994 C280, dark green metallic
1991 190E 2.6, Black
(sold to another forum member)
2003 Chevy Tahoe LT, Redfire Metallic
1989 Mustang GT Cobra Convertible