2005 Volkswagen Polo epc light on and then a jerking noise then car losses power.

I drive a polo 2005.Lately when driving the Epc light comes on,on the odometer the hazard with a circle comes on too, then the car makes a noise like that made when one breaks as an emergency after that the car losses power.The mechanic says there is nothing worng with the car and the dignosis shows nothing.This happens frequently in the morning and the frequency seems to be increasing.Please help its becoming too much