Why Does an Engine Suddenly Misfire?

[VanJonathan]

The reason for sudden engine misfiring is abnormal diesel engine fuel system operation, malfunctioning diesel pump, or fuel injectors not spraying fuel. First, check whether each cylinder is receiving electricity, whether the spark plugs are intact, whether carbon buildup is excessive, whether the engine is burning oil (as oil burning can easily damage spark plugs), and whether high-voltage wires are leaking electricity. Symptoms of the fault: Dashboard warning lights illuminate—the dashboard information is the most intuitive reflection of vehicle status. Difficulty starting: whether multiple attempts are needed to start the engine. Unstable idle: the engine idles roughly with fluctuating RPM. Abnormal noises or odors from the engine compartment. High temperature in the engine compartment. Oil leakage around the cylinder block. Abnormal increase in fuel consumption. Dangers of misfiring: For the entire vehicle, it accelerates wear on moving parts, tends to generate excessive carbon deposits, shortens the lubrication oil service cycle, and poses significant risks to driving safety—especially on uphill starts. A misfiring engine increases load, causing more noticeable body vibration and a higher risk of sudden stalling.