E36 325i 1994Model

Hi, please help me out.. my car engine stops every time. but once i switch it on it runs again. before the engine stops running by it self, it get choked like less gasoline is injected. i am also hearing a noise coming from the front part of the engine where the vanus is. the noise starts only when the engine will start to stop running by it self. Fuel pump is replaced already. A friend of mine was suggesting to change the engine.... i don't know what is exactly the problem. i dont have an experienced mechanic available in my area. Please advise...... thanks...