What are the symptoms of engine misfire in a car?
3 Answers
The symptoms of engine misfire in a car include unstable idle speed, abnormal engine shaking; noticeable decrease in power; difficulty in starting the vehicle, engine prone to stalling; black smoke from the exhaust pipe. The following are the causes and solutions for misfire: Ignition system issues such as eroded spark plugs not firing, damaged high-voltage coils unable to generate high voltage, faulty high-voltage coil relays, or possible ECU malfunctions causing the high-voltage coils not to ignite. Solutions include timely replacement of spark plugs as per the maintenance manual, using a multimeter to check if the high-voltage coil resistance is normal, and professional decoding equipment at a 4S shop for further diagnosis. Fuel injection system problems like insufficient fuel supply pressure, damaged fuel lines, excessive wear of the fuel tank pump, clogged fuel filters, insufficient pressure from the high-pressure fuel pump, clogged or poorly atomizing fuel injectors, or excessive wear of the injector needles leading to fuel dripping, which causes excessive gasoline vapor in the cylinder wetting the spark plugs and preventing them from firing. Solutions include using a fuel pressure gauge to check if the fuel line pressure is adequate; inspecting the fuel tank pump and high-pressure fuel pump for excessive wear and replacing them if necessary; cleaning or replacing fuel injectors based on usage.
Having driven for decades, I've experienced a misfiring cylinder. That time, just as I started moving, the car body shook violently, feeling as uncomfortable as sitting on a massage chair. It was especially noticeable at idle—the entire engine was wobbling. The power dropped significantly; even climbing a small slope was a struggle, and pressing the accelerator to the floor didn't help with speed. Fuel consumption surged—normally, a full tank could cover 500 kilometers, but at that time, it barely managed just over 400. The engine warning light on the dashboard came on, and the diagnosis revealed a faulty spark plug. Ignoring such an issue and driving long-term could damage the engine internals, leading to even costlier repairs. So, if you notice shaking, don't delay—get it checked immediately.
I've been passionate about cars since college, and the misfiring issue in Hyundai vehicles is quite noticeable. After starting, the idle is unstable, and the car shakes like it's dancing disco. During acceleration, the power delivery is intermittent, making the car feel like it's 'coughing.' Fuel consumption spikes instantly, showing a 20% increase over normal levels, and sometimes black smoke or popping sounds come from the exhaust. When connecting an OBD scanner to the diagnostic port, it usually displays fault codes like P0301, indicating which cylinder is misfiring. I recommend paying attention to these signs early on to avoid major problems later.
