Yes, it does save gas. Eco mode means that your car is in its most efficient gear and that it’s braking and accelerating more slowly. This reduces the amount of energy your car consumes and therefore gives you better gas mileage. It’s important to note that eco mode won’t save as much gas on the highway as it will in the city. In general, you’ll get better gas mileage by driving the speed limit instead of speeding or by slowing down gradually rather than slamming on the brakes. But eco mode is still a good way to save gas, especially if you’re stuck in traffic or if you’re driving in a congested area.