Ford Transit 1995, black and white smoke?

Hi,
Every two - three days, after i start my transit for first time in the day, and drive it for about 300m, the engine accelerates on it´s own, a big cloud of black and white smoke is coming out of the exhaust, then the engine is working normally, but still white smoke is coming out, and after a couple kilometers everything is ok.
It also smells like burning oil.
What is causing this.