black smoke on 1991 Dodge Ram Van B250

my van cuts in an out an has hevy black smoke coming from tail pipe and it is realy bad on gas

Asked by for the 1991 Dodge Ram Van B250
Sounds like a fuel control problem, like a vacuum leak or a sensor issue. Have a diagnostic test performed that may focus on that area.
its not showin any codes
A diagnostic test only starts with reading codes. A 1991 vehicle is very limited in diagnostic codes compared to a current year model. Some good manual testing of fuel pressure, air flow, monitoring oxygen sensor performance and barometric pressure is a good start.
1 more answer
tune-up and new fuel filter maybe clean the carb. out with spray