Preheat oven to 350 degree F. Grease and lightly flour a 10-inch fluted tube pan; set aside. In a large mixing bowl combine cake mix, milk, cooking oil, sour cream, rum, eggs, and pumpkin pie spice. Beat with an electric mixer on low speed until just moistened. Beat on medium speed for 2 minutes, scraping sides of bowl occasionally. Pour batter into prepared pan.
Bake for 35 to 40 minutes or until a wooden toothpick inserted near the center comes out clean. Cool in pan on a wire rack for 10 minutes. Remove cake from pan and cool completely on wire rack. Spoon Rum Glaze over cake. Makes 12 servings.
In a small bowl combine powdered sugar, melted butter and rum. Stir in water (1 to 2 teaspoons), one teaspoon at a time, until glaze is a thin consistency.