Sprinkle pork with 1/2 teaspoon each of salt and pepper. Brown pork in hot oil in a large skillet over medium-high heat.
Layer pork and vegetables in a 5-quart slow cooker. Pour broth over vegetables. Sprinkle with remaining 1/2 teaspoon each of salt and pepper. Cover and cook on LOW setting 6 hours.
Stir together flour and butter in a small bowl; gently stir into stew one tablespoon at a time. Increase heat to HIGH setting; cover and cook 30 minutes until thickened, stirring occasionally.