Causes of Engine Misfire

[OJasmine]

Here are the fault causes leading to engine misfire: 1. Poor contact or excessive resistance in the ignition coil corresponding to the cylinder, or a damaged ignition coil. 2. Leakage or open circuit in the cylinder's distributor wire, excessive or insufficient spark plug gap, or carbon buildup between electrodes. 3. Air flow. The powertrain control module detects an air flow (MAF) sensor output below normal air flow, resulting in an overly lean air-fuel mixture. 4. Intake system. Air leaking into the intake system bypasses the air flow sensor, causing an overly lean mixture condition. Check for disconnected or damaged vacuum hoses. 5. Improper installation or malfunction of the crankcase ventilation valve, or vacuum leaks at the throttle body, EGR valve, and intake manifold mating surfaces. 6. Poor operation of the EGR valve, leading to an overly lean mixture or excessive exhaust gas recirculation flow. 7. Fuel pressure. Faulty electric fuel pump, clogged fuel filter, or malfunctioning fuel pressure regulator causing improper fuel pressure, resulting in an overly lean mixture. 8. Fuel injector. Dirty or stuck fuel injector causing poor fuel atomization; damaged O-ring seal on the fuel injector; faulty fuel injector control circuit causing continuous or no fuel injection. 9. Impurities in the fuel, indicating poor fuel quality. 10. Engine mechanical faults causing uneven cylinder compression pressure. 11. Incorrect engine timing or abnormal valve clearance.

[LeilaniDella]

Sometimes when I'm driving, the engine suddenly starts shaking, feeling like it's trembling, which is usually a misfire. Common causes include aging spark plugs or damaged ignition coils, leading to unstable ignition; there are also fuel system issues, such as clogged fuel injectors or insufficient fuel pump power, preventing fuel from reaching the cylinders. On the air side, problems like a dirty air filter or leaks in the intake system can cause an imbalance in the air-fuel mixture, making it difficult to ignite. Sensor failures are another possible cause, such as misjudgment by the crankshaft position sensor, leading to incorrect engine control by the ECU. I remember last time I spent some money fixing the ignition system to resolve the shaking issue. If you notice any abnormalities while driving, it's best to go to a professional shop immediately to check it out, to avoid causing bigger problems. Safety is more important than anything, especially when driving long distances—extra caution is necessary.