What Causes Engine Misfire in Cars?
3 Answers
Below are the related causes of engine misfire in cars: 1. Main manifestations of engine misfire: The primary symptom is when one or multiple cylinders fail to operate or function improperly, resulting in cylinder misfire. 2. Ignition system faults: Such as incorrect ignition timing, abnormal spark plug gap, carbon buildup or breakdown, high-voltage wire leakage, open or short circuits in ignition coils, and faults in ignition modules or wiring. 3. Fuel supply system faults: Including excessively low or high fuel pressure, open or short circuits in fuel injector coils, mechanical sticking, etc. 4. Intake system faults: Such as clogged air filters or air leaks in the intake system. 5. Insufficient cylinder compression: Caused by faults in the valve train, poor sealing between pistons, piston rings and cylinder walls, or damaged cylinder head gaskets.
I've experienced misfire issues over years of driving, mainly due to ignition system failures like worn spark plugs or severe carbon buildup causing poor ignition, as well as aging ignition coils with electrical leakage affecting spark intensity. Fuel supply problems are also common - clogged fuel injectors or insufficient fuel pump pressure can create an overly lean air-fuel mixture, easily causing misfires in certain cylinders. Additionally, mechanical faults like uneven cylinder pressure or poor valve sealing lead to insufficient compression. Sensor malfunctions, such as faulty oxygen sensors misreporting the air-fuel ratio, can trigger idle shaking and weak acceleration. Preventive measures are simple: regularly inspect and replace spark plugs, maintain clean fuel systems using additives - this reduces misfire risks and extends engine life.
I believe the most common cause of car misfires is electrical faults. Worn-out spark plugs or incorrect gaps directly lead to ignition failure, and short circuits in ignition coil high-voltage wires are also often to blame. There are many fuel-related reasons as well—unstable fuel pump supply disrupts the air-fuel mixture ratio, and clogged fuel injectors directly affect spray performance. External factors like weather should not be underestimated, as cold starts make fuel harder to vaporize, increasing misfire risks. Additionally, loose wiring harness connections causing poor contact can interrupt signal transmission and result in misfires. Using a diagnostic tool to read fault codes promptly helps quickly identify and fix the issue.
