I had replaced the MASS AIRFLOW SENSOR a couple of weeks ago because during cold starts I would have to wait a couple of minutes just to warm up the car before the car could move forward, it would basically jerk back and forth and stall before pressing on the gas. Now, that doesn't happpen, after it was replaced no more hesitation, but now I don't hear the engine, no more rough idling, the engine is quiet as if It is about to die on me. While in drive and when at a long stoplight, or railroad crossing, my engine would just shut off, its as if it never reaches idle. I was thinking it can be the AIR BYBASS VALVE but there many names for that. I really think it soething to do with my idling. Anyone please help....I have had my car for four years and I never had a problem until now?!?