Your coolant temp switch in the intake manifold may be going bad as it controls fuel mixture as it gets warmer. That may explain the black smoke. The timing is controlled by the ecm. But you can set initial timing by disconnecting the single brownish wire behind/under the glove box. That seperates it from the ecm so you can set timing by the distributor. Book says to set it to 0 degrees. I have better luck at 4 degrees btdc.