Symptoms of Engine Misfire?

[KathrynAnn]

Automobile engine misfire manifests as: 1. Unstable idling and abnormal engine vibration; 2. Significant power reduction; 3. Difficulty starting the vehicle and engine prone to stalling; 4. Black smoke emitted from the exhaust pipe. The primary causes of engine misfire stem from the ignition system and fuel injection system. Severe burning of the contacts in the distributor cap of the ignition system can cause spark jumping, mostly occurring between corresponding terminals on the cap, leading to erratic idling and severe power loss. Faulty ignition coils can also result in misfire, often causing severe burning of the distributor cap. Issues with the ignition coil most commonly lead to sudden severe power loss and engine stalling.

[LeReese]

Last time I took my old car on the highway, it suddenly started shaking violently, as if it was about to fall apart. The accelerator felt weak and unresponsive, the exhaust pipe was popping loudly, and the yellow engine light on the dashboard was flashing. I immediately pulled over to check and found black smoke coming from the exhaust with a strong gasoline smell, and the steering wheel was vibrating so much at idle that it made my hands go numb. This is most likely a cylinder misfire—it could be due to carbon buildup on the spark plugs preventing ignition, a burnt-out ignition coil, or a clogged fuel injector. If not fixed in time, the unburned gasoline could even ruin the catalytic converter.

[DelChase]

My little blue car started shaking like it was gasping for breath when I turned it on, with the tachometer needle dancing up and down. It drove like it was climbing a hill with a heavy load, and the fuel consumption suddenly soared from 7 liters to 11 liters. The most obvious symptom was the exhaust pipe sounding like a tractor with a 'clattering' noise, and at red lights, the car body shook so much that even the rearview mirror vibrated. The mechanic said that such misfiring symptoms are most commonly caused by aging spark plugs, followed by checking if the ignition coil is leaking electricity. Using an OBD scanner to read the fault codes, it indeed showed a P0304, indicating a misfire in cylinder 4.

[OAlexa]

At a car meet, I heard a fellow enthusiast complain about the eye-watering stench from his car's exhaust when it was misfiring. I've encountered an even worse scenario: the car shook like a massage chair during cold starts but improved after warming up, only to find out it was due to rodent-chewed spark plug wires. When a cylinder misfires, the engine goes into self-protection mode—the ECU either cuts off fuel injection or stops ignition for that cylinder, which is why you can feel one side of the exhaust pipe cold and the other hot. Long-term misfiring can also allow unburned gasoline to seep into the engine oil, diluting the lubricant and damaging the engine.