2000 Renault Megane car jerking while drive, like no power I

My mechanic cheangs 4 coil pack and map sensor he put on the computer and nothing come up on system now he is saying change crankshaft sensor please help me I do not know what I do I spent so much money but no luck.
Please let me know what you think what shell I do

many thanks

Hi, Check your engine breathers may be blocked with old thick oil, blow out change your oil with correct oil, and change oil filter.
Ps. Before you do this remove oil filler cap and drive your car a short distance hopefully not two much mess if no problem its may be the eng/breathers, you have to use the correct oil (25/50) etc check with your supplier.