Ensure all of your injector connectors are properly seated and there are no leaks near the fuel manifold.
Confirm O2 sensors are in good working order. I had a truck in my shop for some work and they had rough idle and black smoke... was a bad O2 sensor and #6 injector connector was loose.
Confirm O2 sensors are in good working order. I had a truck in my shop for some work and they had rough idle and black smoke... was a bad O2 sensor and #6 injector connector was loose.