1991 Buick Century

First, I believe the vehicle should be fuel injected. Does yours have a carb? Second, when you see the smoke, is it coming out of the (carb) throttle body or around it? Is it actually smoke or fuel vapor / mist? Do you smell anything burning? Has the check engine light come on? Have you checked fuel pump pressure? Did this happen all at once or slowly over time? When was the last tune up?

Sorry for having so many questions, but I need to eliminate things to get to the problem. Let me know.

Joe