What is the meaning of OBD-II code P0303, and what are the possible causes and solutions for this code to be generated?

The ECU sets the P0303 code when multiple misfires are detected from cylinder 3, causing the Check Engine Light to come on and the vehicle to enter failsafe mode. The light remains on until the issue is fixed. There are several possible causes for a P0303 code, such as: -Defective spark plugs -Problems with fuel injection -Issues with the plug wires, cap, rotor, or coil pack (depending on the vehicle) -Mechanical engine problem -Leaks in the intake air system To diagnose the problem, a mechanic will typically use a scan tool to check for any current, history, or pending codes, take a test drive, perform a visual inspection, check the misfire counter and long-term fuel trims, and in some cases, they may also inspect the spark plugs. The resolution to the P0302 code will vary based on the underlying cause, which may include replacing spark plugs for all cylinders, replacing the cap and rotor, spark plug wiring or coil pack if necessary, repairing intake air leaks, fixing fuel issues, or repairing mechanical engine issues. A scan tool that may view live engine data is crucial in diagnosing P0303, allowing technicians to see long-term fuel trims, intake air sensor readings, fuel injector operation, and misfire counters to determine the cause. Spark plugs, cap and rotor, and spark plug wires are commonly replaced at service intervals, with coil packs generally lasting longer but needing to be replaced as a set if they fail.