acceleration problem

i have a 91 tsi fwd and i was wonderin why when i accelerate my car takes off real quick but then at about 5 grand it will jump real bad and shoot out black smoke. any one know what it is

What do you mean by the "boost control thing"?

Any CEL's?

the BCS(Boost Control Solenoid)

i think it might be my turbo sucking in to much air but i thought that was controlled by my BCS.