What are the causes of engine misfire in cylinder one?
3 Answers
Engine misfire in one cylinder may be caused by the following reasons: 1. Ignition system failure: Ignition system failure is the main cause of engine misfire in one cylinder. Ignition system failures include spark plug failure, ignition coil failure, fuel injector failure, etc. When there is a problem with the car's ignition system, the fuel and air mixture cannot be ignited normally, leading to engine misfire, which can result in reduced car power, engine vibration, and other issues. In this case, the car's ignition system should be inspected, and spark plugs should be replaced immediately, along with cleaning the fuel lines. 2. Wiring system: If one cylinder of the car misfires but there is no engine vibration, it is mostly due to wiring issues. In this situation, the car's wiring should be checked for any short circuits or open circuits and repaired promptly. 3. Engine failure: There are many reasons for engine failure, including excessively high engine temperature, poor engine oil quality, etc. This situation is quite complex and requires professional inspection at a repair shop or 4S store.
An experienced driver tells you I've encountered this several times. The most common cause of a misfire in cylinder one is a dead spark plug, either fouled by carbon deposits or with eroded electrodes. A failing ignition coil is another culprit—cracked insulation causing electrical leakage can directly cause the spark plug to fail. Clogged fuel injectors or faulty coils can also cause trouble; if fuel isn't injected on time, the cylinder will misfire. Also, be wary of low cylinder compression, which could be due to leaking valves or worn piston rings. If you notice rough idling like a massage chair, a rotten-egg smell from the exhaust, and the car jerking, check the trouble codes immediately. P0301 clearly points to cylinder one—don't keep driving it hard, or you might ruin the catalytic converter.
Just learned this trick at the repair shop and sharing with you. For a misfiring cylinder, follow this sequence: First unplug the ignition coil connector and listen for sound changes—no reaction means an issue with that ignition circuit. Remove the spark plug; if it's black and greasy, just replace it. Swap the ignition coil with a neighboring one—if the problem moves, that coil is faulty. Test the fuel injector's resistance; if it exceeds 14 ohms, it's likely done. A compression test is most accurate—if the pressure difference between cylinders exceeds 15%, there's definitely a problem. Recently helped a neighbor fix this exact issue—just replaced the spark plugs for a few bucks and it worked. Don’t cheap out on parts; aftermarket ones might fail again in three months.
