Preheat your oven to 350°F (175°C). Grease your 9x5 inch loaf pan with a little vegetable oil or line it with parchment paper for easy removal.
In a medium bowl, whisk together the flour, baking soda, baking powder, salt, cinnamon, nutmeg, and cloves to ensure even distribution.
In a large bowl, whisk the sugar and vegetable oil until combined. Add the pumpkin puree, eggs, and vanilla extract, mixing until smooth and well incorporated.
Gradually add the dry ingredients to the wet ingredients, stirring gently with a rubber spatula just until combined. Avoid overmixing; the batter should be thick with a few streaks of flour remaining.
Fold in the chopped walnuts or pecans if using for added crunch.
Pour the batter into the prepared loaf pan and smooth the top. Bake for 60-70 minutes or until a toothpick inserted into the center comes out clean. Tent with foil if top browns too quickly.
Allow the bread to cool in the pan for about 15 minutes before transferring to a cooling rack. Slice and enjoy warm or at room temperature.