What are the causes of intermittent misfire in one cylinder?
3 Answers
Here are the specific reasons for intermittent misfire in one cylinder: Clogged or aged fuel injector: As the vehicle ages, carbon deposits accumulate over time, leading to clogged fuel injectors; fuel injectors subjected to long-term high-pressure gasoline flow can experience severe aging. Issues with spark plugs: Spark plugs are one of the most easily damaged car components, with ordinary copper-core spark plugs having a lifespan of around 30,000 kilometers. In actual usage, even if the spark plugs have not reached their expected lifespan, carbon deposits can still cause engine misfire. Ignition coils and cylinder wires: Damage to these components is the most common cause of engine misfire. If these parts malfunction, the spark plugs cannot ignite properly, resulting in misfire.
I often experience occasional engine shaking when driving on the highway, which is intermittent misfiring in one cylinder. The most common cause is excessive carbon buildup on the spark plugs or improper gap, leading to unstable ignition. Worn-out spark plugs are prone to this issue, especially when driving frequently on dusty roads where buildup occurs quickly. Aging or moisture-damaged ignition coils can also fail, causing intermittent sparks. I remember my engine shaking badly after a long trip last time, and replacing the coil solved the problem. Another cause could be clogged or leaking fuel injectors, which result in insufficient fuel spray and incomplete combustion—cleaning the injectors can help. Don’t forget to check for loose high-voltage wire connections, as poor contact can cause intermittent power loss. Early repairs can prevent bigger issues, and maintenance isn’t expensive.
From years of experience in car repair, this intermittent misfire is 80% likely related to spark plug issues. Dirty or worn spark plugs can cause poor ignition. Other common causes include internal short circuits or external corrosion in ignition coils, especially after prolonged driving in humid environments. Moving on to the fuel system, clogged injector nozzles or uneven fuel spraying due to impurities can trigger misfires—cleaning them usually solves the problem. Compression issues like valve leaks or worn piston rings may indirectly cause misfires too. Wiring problems such as loose or oxidized connectors are frequent culprits; unstable connections lead to erratic currents. Sensors like faulty crankshaft position sensor signals also need checking. For DIY inspection, start by replacing spark plugs and checking coils. If the issue persists, then visit a professional shop.
