MIX FLOUR AND SUGAR; SET ASIDE. IN A SAUCE PAN, MIX MARGARINE, VEGETABLE OIL, COLA, AND COCOA. BRING MIXTURE TO A BOIL. POUR IMMEDIATELY OVER FLOUR MIXTURE. ADD REMAINING CAKE INGREDIENTS, MIXING THOROUGHLY. POUR INTO 9 X 13 INCH GREASED PAN. BAKE AT 325 DEG F FOR 40 MINUTES. WHEN CAKE IS ALMOST DONE BEGIN MAKING ICING. BRING MARGARINE, COCOA AND COLA TO A BOIL. BEAT IN POWDERED SUGAR. SPREAD ICING ON CAKE WHILE WARM. ALLOW TO COOL BEFORE CUTTING INTO LARGE SQUARES. MAKES 12 SERVINGS.