Combine cake mix, flour, pumpkin pie spice, water, oil, eggs and sour cream in a large bowl.
Mix using a hand mixer until you have a thick batter.
Pour batter evenly into two loaf pans that have been lined with parchment paper and sprayed with nonstick spray.
Bake at 350 degrees for 55-60 minutes or until a toothpick inserted in the center comes out with only a few crumbs.
Allow the pumpkin bread to cool in the pans for 15 minutes before turning out onto a cooling rack.