Step 1: Preheat your oven to 350°F (175°C) and grease a 9×5 inch loaf pan with butter or non-stick spray.
Step 2: In a medium bowl, whisk together the flour, baking soda, baking powder, salt, cinnamon, nutmeg, and cloves until well combined.
Step 3: In a large bowl, beat the vegetable oil, granulated sugar, and brown sugar together until smooth. Add the eggs one at a time, beating well after each addition.
Step 4: Stir in the pumpkin puree and water (or orange juice) into the wet mixture until fully incorporated.
Step 5: Gradually add the dry ingredients to the wet ingredients, stirring gently with a spatula just until no flour streaks remain. Do not overmix.
Step 6: Gently fold in 3/4 cup of the toasted walnuts. Pour the batter into the prepared loaf pan and smooth the top.
Step 7: Sprinkle the remaining 1/4 cup of walnuts over the top of the batter. Bake for 60-65 minutes, or until a toothpick inserted into the center comes out clean.
Step 8: Allow the bread to cool in the pan for 10 minutes before transferring to a wire rack to cool completely.