81 4X4 p/u runs rough wont idle and smokes when cold

Hi there. I have an 81 toyota 4x4 pick up with 150,000 org. Miles. It recently had that carb. Rebuilt and adjusted to pass CA smog. This took place in the LA area but now I am in the cental valley (Fresno). The problem that I am haveing is it runs rough, won't idle, and smokes (black) when cold. Once warm it runs great. This Truck has been taken very nice care of so the vacc. Lines seem to be all in good shape. It does seem as though the catalytic converter might be going out (there is a slight sulfer smeel) and the O2 sensor needs to be replaced. I was thinking that I need to fix the cold runing issue first to advoid the burning out of the smog stuff, but could that be the problem?

thanks for hearing my ploblem
please help
josh