Code P0300 for a 2008 Toyota Highlander indicates a “Random/Multiple Cylinder Misfire Detected.” This means the engine’s cylinders are not firing correctly, which can lead to poor performance, rough idling, reduced fuel efficiency, and even potential engine damage if left unresolved. Common causes include faulty spark plugs, ignition coils, fuel injector issues, vacuum leaks, or problems with the engine’s timing. In some cases, low fuel pressure or even a failing catalytic converter can trigger this code. Diagnosing it properly may require checking the specific misfiring cylinders and addressing the root cause, so using an OBD-II scanner is essential.
