Contrary to what it looks like, Effuel ECO OBD2 does not affect the fuel quantity. It uses the ECU function to improve the fuel requirement of the car and having it installed in the car also improves the drive and road performance no matter if the car is on a short route or long route. As already mentioned, you may save up to 30% of your fuel cost with no compromise on car functions and up to a 35% increase in the overall engine power.Click Here finance.yahoo.com/news/effuel-reviews-2021-effuel-eco-215900802.html