Heat oil in a casserole dish over medium heat. Coat steak strips with flour. Working in batches, place strips in hot oil. Fry until browned on both sides. Remove to a warm platter. When all meat is browned, return meat to casserole dish and stir in onions, mushrooms, salt, pepper, gravy mix and stewed tomatoes. Bring to a boil then simmer about 30 to 45 minutes.
About 20 minutes before steak is finished, fill a large pot with water and bring to a boil. Add egg noodles and cook until al dente, about 8 to 10 minutes; drain.