Preheat the oven to 325°F (or 350°F if your oven runs cool). Grease and line a loaf pan.
In a mixing bowl, sift together the flour, salt, baking soda, baking powder, and pumpkin pie spice.
In another large bowl, cream together butter, white sugar, and brown sugar for 2 minutes until light and fluffy.
Add eggs one at a time, mixing well after each addition.
Mix in vanilla, sour cream, and pumpkin purée until smooth.
Gradually add the dry ingredients in thirds, mixing on low speed until a smooth batter forms.
Pour the batter into the prepared loaf pan and bake for about 60 minutes, or until a toothpick inserted in the center comes out clean.
Cool completely before glazing.