What Causes Throttle Shaking?
3 Answers
Throttle shaking can be caused by the following reasons: 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 acceleration shaking. 2. Cracks in the ceramic part of the spark plug, leading to no ignition in one cylinder, which causes acceleration shaking. 3. Poor quality gasoline, resulting in poor atomization by the fuel injector and incomplete combustion of the air-fuel mixture in the cylinder, leading to idle shaking. 4. Uneven tread on the four wheel tires, such as bulges or foreign objects. 5. Loose wheel bearings causing vehicle shaking during driving.
I've encountered quite a few cases of throttle vibration during my car repair experience. The most common cause is ignition system issues - either the spark plug gap is too wide or the ignition coil has aged, leading to irregular operation in a particular cylinder. The fuel system should also be checked; clogged fuel injectors or insufficient fuel pump pressure can cause vibration when the fuel supply can't keep up. Then there's the engine mounts - if the rubber pads are worn out, the engine will shake violently when under load. Carbon buildup in the intake tract is another culprit; when airflow is restricted, the throttle response becomes jerky. My recommendation is to first inspect the spark plugs and throttle body - these account for about 80% of vibration issues. If the problem persists after replacement, then you'll need to check the wiring or the ECU.
I've been driving for thirty years and encountered all kinds of engine shaking issues. In the carburetor era, it was usually due to poor fuel delivery, but nowadays with fuel-injected cars, it's mostly caused by excessive carbon buildup in the throttle body or worn-out spark plugs. Once when I was driving an old Passat, it would shudder every time I accelerated - turned out the engine mount was cracked. If the shaking only occurs at specific speeds, like being particularly noticeable between 60-80 km/h, there's an 80% chance it's due to improper wheel balancing. Remember to check the air filter too - when it gets too dirty and affects airflow, that can also cause shaking. Try using some fuel system cleaner additives; sometimes poor fuel quality with too many impurities can trigger shaking as well.
