What is causing my car to have black smog come out the exhuast after she warms up?

When I start her, she will start no problem, then she starts shaking. I will drive it right away, but the minute that she gets up to operating temp, around 90 degrees, she will shift funny, spit out black soot, and I will have to push the gas pedal to the floor to get her to do freeway speeds.
So far we have done a tune up. We run like sea foam, or b12, She also smells rich, I put the highest level of gas in her.