EFI Live is a software and hardware solution designed for tuning and modifying the performance of vehicles, particularly those with GM and Dodge engines. It allows users to adjust various parameters in the engine control unit (ECU) to enhance performance, fuel efficiency, and overall drivability. The system includes a handheld device that connects to the vehicle's OBD-II port, enabling real-time data monitoring and adjustments. Users can create custom tunes, read diagnostic trouble codes, and log performance data, making it a popular choice among automotive enthusiasts and professional tuners alike.