fuel trim

**Fuel Trim** refers to the adjustments made by a vehicle’s engine control unit (ECU) to the amount of fuel injected into the engine to maintain optimal combustion and efficiency. These adjustments compensate for variations in air intake, fuel quality, and engine conditions to ensure the engine runs smoothly, reduces emissions, and maximizes fuel economy. In automotive diagnostics, monitoring fuel trim values helps identify issues such as vacuum leaks, faulty sensors, or fuel delivery problems.