Failure in Peugeot 306 xs 3 doors 1.6 year 2000

When I move it very slowly, it almost does not, it moves very little, I imagine that it would be something of a engine taco, the strange thing is that in motion does not do it more, no matter how much it accelerates it suddenly, it only does it when I move it and it is totally still, it is more yesterday to move it in second and did almost nothing.