Place cut roast in freezer bag with flour and shake to coat; brown meat in oil in skillet then place in crockpot. Add potatoes, onion, celery and carrots to crockpot. Take packet of beef stew mix and thoroughly combine with 3 cups of water. Pour over ingredients in crockpot and cook on HIGH for 4 to 6 hours or LOW for 6 to 8 hours. Add peas about one hour before end of cooking time.