Vehicle repairing, stalling problem

Hi guys! I have a Toyota premeo with a 4A engine, the problem is when i start it’s running rough but at a normal idling when i put it in gear or when it stalls sometimes even reving it on during idling it stalls. I tried changing the plugs, coils, high tension cables, fuel pump, air cleaner and the throttle body but still it stalls when put in gear or braking. What else could cause this problem