1994 Ford Taurus Mixed of rich gas

Engine Mechanical problem
1994 Ford Taurus 6 cyl All Wheel Drive Automatic 111k miles

My car is pushing out black smoke through the exhaust. SOmething isn't alowing the car to breat hwhen you accerate it only goes for so long and then cuts itselfs off. We checked the timing it's fine. We changed the plugs and wires. Any clue to what part in the fueling system that may be causing this problem?

Also to check the light or code for the check engine light where do I put the paper clip?