1988 Bronco2 hesitation

Hello, I have an 88 bronco deuce 2.9 5spd with 165k, having trouble with hesitation, rough idle and fuel consumption. I recently bought the vehicle. It was the previous owners daily driver, which apparently ran fine until it sat for 6 months or more without being driven, except from place to place in the yard a couple times, before being sold to me. It seems to run great at times, then at low to mid throttle it will lose power and skip, blowing black smoke, but when you floor it, it kicks in and goes, let off and it runs bad again. You can smell the rich exhaust when this occurs. This is an intermittent thing, sometimes I can drive 5 miles without a skip. Same goes for the idle, sometimes its great, sometimes its rough and stalls, warm or cold, it acts the same. It also has poor gas mileage which I assume is from this problem. I have changed the air and fuel filters, temp sensor, map sensor, pressure regulator. Have also added fuel injection cleaner and drygas. I have NOT changed the cap, rotor, wires, or plugs, as I assumed it was a fuel issue, but I am probably wrong. I would greatly appreciate any input. Thanx :)