What should the tachometer read when the vehicle is at idle?

When a vehicle is at idle, the tachometer should read between 500 and 700 RPM for optimal engine performance. This range indicates that the engine is running smoothly and efficiently without any additional load, allowing for proper functioning of the idle system. An RPM reading below this range could suggest that the engine is struggling to maintain idle, which could lead to stalling or other mechanical issues. Conversely, readings above this range may indicate an overly high idle RPM, which can lead to inefficient fuel consumption and potential long-term wear on engine components. Maintaining the correct idle speed is essential for ensuring that the vehicle operates as intended and meets safety and performance standards.