Efficiency is a powerful trip computer for OBD2 enabled vehicles that is focused on helping you maximize your fuel economy.Please report any problems you may encounter. Make sure to include your car model, year, OBD2 adapter, phone model, and Android version you’re using.App Requirements:- A OBD2 enabled vehicle built in 1996 or newer- ELM327 Bluetooth Adapter- An Android 2.1 phone/device or newer with Bluetooth capabilities.Support:For Help visit http://efficiencyapp.wordpress.com/help/ or email to [email protected] Tags: Efficiency, OBD2, OBDII, Elm327, Ecu, MPG, fuel economy, fuel efficiency, Eco meter, ecometer, econmeter, green meter, ECU, car, truck, speed, rpm, gas, OBD, OBD-II.