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

2 answers 2 comments
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.
tune-up and new fuel filter maybe clean the carb. out with spray