What causes the engine malfunction light to suddenly come on and the car to shake when accelerating?
3 Answers
Reasons for the engine malfunction light suddenly coming on and the car shaking when accelerating: 1. Damaged spark plugs, where the wear of the spark plug electrode gap leads to insufficient spark ignition, causing incomplete combustion of the air-fuel mixture and resulting in shaking during acceleration; 2. Poor quality gasoline, leading to inadequate atomization by the fuel injectors and incomplete combustion of the air-fuel mixture in the cylinder, which can also cause idle shaking; 3. Faulty oxygen sensor, where damage to the oxygen sensor or its connector, or loosening, can cause the air-fuel mixture to be too lean or too rich, triggering the malfunction light; 4. Faulty mass air flow sensor, which measures the amount of air intake and converts it into an electrical signal sent to the Engine Control Unit (ECU), indirectly allowing the ECU to determine the amount of fuel to inject. If the mass air flow sensor or its circuit malfunctions, the ECU will not receive the correct air intake signal, leading to improper fuel control and causing the air-fuel mixture to be too lean or too rich, preventing the engine from operating normally.
The engine warning light suddenly came on, and the car shakes when I step on the gas. As an amateur car repair enthusiast, I often see this issue, and I think it mainly stems from engine misfiring. Simply put, the spark plugs or ignition coils might be faulty, causing a cylinder to misfire, making the car shake noticeably when accelerating. It could also be due to clogged fuel injectors or poor-quality gasoline, leading to incomplete fuel combustion. An aging fuel pump can also cause similar shaking. More importantly, don't keep driving with the problem—prolonged engine misfiring can damage the car. Quickly grab an OBD scanner to read the trouble codes; most auto repair shops have one. Check if it's a P0300 misfire code or something else. Preventive measures include regularly replacing spark plugs and inspecting the fuel system—don't skimp on small expenses and end up with big problems. For safe driving, pull over and stop first.
I once experienced such a dangerous situation. As an ordinary car owner, the engine light coming on plus shaking is really frightening! I remember it was the first time I encountered this—stepping on the gas pedal felt like an earthquake. Later, I learned it was due to misfiring, possibly because the spark plugs had no power or the ignition coil was short-circuited. A clogged fuel filter could also be the culprit, causing unstable gasoline supply. A faulty air flow sensor can also affect the air-fuel mixture ratio. Once the warning light comes on, it needs immediate attention. Don’t panic—slow down immediately and pull over, avoiding high-speed driving. You can check simple things yourself, like loose fuses, but it’s best to send it for professional repair. Pay attention to regular maintenance schedules during daily driving and avoid exceeding the service intervals.
