what is causing truck suddenly accelerates like I floored it, blows black smoke.

What is your question?

It does not happen all the time but it is frightening when it suddenly does. I must turn off the motor to stop it. It seems to affect my transmission as well at times the motor begins to rap with tinny sound no compression and transmission does not act as though it is engaged does not smoke then. Has started to get worse with lunging as though I am out of fuel or it is out of time. If I had a distributor I would swear the ground wire came off or it jumped time. Help