What Causes Engine Shaking When Accelerating?
4 Answers
Reasons for engine shaking when accelerating: 1. Spark plug failure: Spark plugs have electrodes, and the gap between them will increase with prolonged use, affecting the ignition intensity of the spark plug. Over time, carbon deposits will also accumulate on the electrodes, which can further impact the spark plug's ignition energy. 2. Engine misfire: An engine misfire can also cause shaking. It is necessary to check whether the ignition coil of the affected cylinder is damaged. After removing the spark plug, a special sticker should be used to cover the spark plug hole to prevent foreign objects from falling into the cylinder. When installing the spark plug, a professional torque wrench should be used to tighten the spark plug to the specified torque. If the spark plug is not tightened sufficiently, it can lead to cylinder leakage. If it is overtightened, the spark plug may break.
My car had the same issue last time, shaking badly when stepping on the gas. It's probably a problem with the ignition system, most commonly due to worn spark plugs or faulty ignition coils. Driving habits matter too—constant low-RPM driving leads to more carbon buildup, and clogged fuel injectors causing poor fuel supply can also result in shaking. The rubber parts in the engine mounts can crack over time, reducing vibration damping and transmitting more shake. Other possibilities include leaking high-voltage wires, a dirty throttle body, a clogged fuel filter, or incorrect air-fuel ratio. The key is not to delay—take it to a repair shop to read the trouble codes, which speeds up diagnosis. You can also try adding a bottle of fuel system cleaner to remove carbon deposits; sometimes that helps.
I've experienced this before, where the car jerks during acceleration. It could be due to a misfiring engine, where one of the spark plugs or ignition coils isn't working properly. Another possibility is an incorrect air-fuel mixture, insufficient fuel supply from the fuel line, low fuel pump pressure, or a clogged fuel injector causing this issue. Sometimes, poor tire balance can also be mistaken for engine vibration. For older cars, pay special attention to the engine mounts; if the rubber is aged and cracked, it loses its cushioning effect. I recommend starting with the simplest checks, like how long the spark plugs have been in use. If they've been used for over 40,000 kilometers, try replacing them. If the cause still can't be found, using an OBD scanner to read the data stream is the most reliable method.
I've fixed this issue many times. The most common causes are incorrect spark plug gaps or electrode erosion, leading to unstable ignition. Cars with slipping clutches can also produce similar shaking sensations during rapid acceleration. Also, pay attention to the engine mounts - if the lower mount rubber cushion cracks, it will cause vibrations during power delivery. In turbocharged vehicles, a faulty blow-off valve can cause unstable boost pressure, and sudden pressure drops will make the car jerk. Air intake system leaks, such as cracked pipes affecting the air-fuel ratio, can also cause shaking. For self-diagnosis, check if there are any warning lights on the dashboard and observe whether there's any difference in shaking between cold and warm engine conditions.
