1997 Volkswagen Golf stalls

I have a Golf Volkswagen 1997 GL, 2.0 liter automatic. Only 40k clicks.
Recently has check engine on and off, black smoke, and very rough idle. Stalls on traffic lights, and and drive is not constant.

I drove in highway, maybe to make it work, no change.

I replaced sparks plugs and distributor cap. No improvement.