Combine sugar, oil, eggs and vanilla in a large mixing bowl. Beat at medium speed with a handheld mixer.
Combine 2½ cups flour, baking soda, salt and cinnammon. Gradually add dry ingredients to wet, using low speed on electric mixer, until well blended.
Dredge apples and pecans with remaining ½ cup flour. Fold into batter. Spoon batter into a greased and floured 10 inch Bundt pan. Bake at 325º for 1 hour and 30 minutes or until cake tester inserted in center comes out clean. Cool in pan for 15 minutes, then remove from pan and let cool completely.