1997 Nissan Altima

Hi!
My daughters Altima runs great intermittenly then runs rough and stalls, while driving, at a light, pulling into the driveway, whenever. It had a check engine light on and when the codes were read it coded for a bad EGR valve and knock sensor. I have since replaced both plus new fuel filter, cap and rotor, spark plugs, spark plug wires and cleared the codes. The vehicle still did the same thing, NO check engine light though, so I thought maybe they were bad/new out of the box and replaced them again. I HATE REPLACING THE KNOCK SENSOR! Anyway the car is still doing the same thing. Runs great intermittently but then starts to run rough and die, NO check engine light. The car starts right up afterwards, runs great for awhile than the same thing and NO check engine light. Any help would be greatly appreciated. Thank You.