Preheat oven to 375 degrees F. In large bowl, whisk flour with baking soda, pie spice and salt.
In another bowl, combine sugars, pumpkin, buttermilk, oil and egg. Whisk until well blended.
Stir in dry ingredients just until completely incorporated. Fold in pecans. Spoon batter equally into 12 oiled muffin cups and bake 20 to 25 minutes or until muffins spring back when lightly touched in centers. Remove from pan and cool on wire rack. Serve warm or at room temperature.