combine egg, with soy sauce, salt and pepper. Add diced pork and marinate at least 20 minutes. combine cornstarch, vinegar, sugar and tomato sauce to taste in a saucepan and mix well. heat quickly, stirring until sugar dissolves, set aside. preheat oil for deep frying in a large heavy skillet. remove pork from marinade and dust with flour. then deep fry evenly, drain and add to sauce in the saucepan. cook about 3 minutes stirring occasionally. serve at once.