Mix flour, baking soda, baking powder, cinnamon, pumpkin pie spice, and salt in a bowl.
In another bowl, mix oil, eggs, granulated sugar, brown sugar, vanilla, and pumpkin. Combine this mixture with wet ingredients (from Step 2) until well-blended.
Spread the batter into your prepared pan and bake for about 36 minutes, or until a toothpick poked in the middle comes out mostly clean.
Let the cake cool in the pan on a rack for 45 minutes, then put it in the fridge.