i know that the "eco" mode is supposed to maximize gas efficiency. what really happens at different points (cruising, passing, accelerating, etc.) when the eco mode is used? do the gears change differently from, say, "touring"; does the cylinder usage change from 8 to 4 differently--if so, specifically how differently from when in another mode? ive read the manual, could not find any help. does anyone have detailed knowledge or written summary?