Why Does the Car Shake at Low Speeds?

[DeTheo]

Here are the reasons why a car may shake at low speeds: Dirty Throttle Body or Carbon Buildup in Fuel Injectors: Engine carbon buildup is the most common cause of car shaking. Among all areas of carbon buildup, the most frequent issues are a dirty throttle body or excessive carbon deposits in the fuel injectors. Therefore, when a vehicle experiences shaking, the throttle body and fuel injectors should be checked first. If the throttle body is found to be dirty or the fuel injectors have excessive carbon buildup, they should be cleaned promptly using fuel injector cleaner and throttle body cleaner. Worn Engine Mounts: Engine mounts, also known as engine supports, are part of the engine's vibration damping system. They absorb minor vibrations when the engine is running. If the engine mounts are faulty, these vibrations can transfer to the steering wheel and the cabin, causing shaking at idle. Uneven Tire Balancing: Whether it's standard steel wheels or lightweight alloy wheels, they can become deformed or cracked under certain external forces. Wheel deformation can cause shaking while driving, as can uneven wheel balancing. Additionally, incorrect wheel alignment can also lead to shaking during driving.

[Vernon]

With years of experience in car repair, I've found that shaking at low speeds is quite common. Causes include engine-related issues like aging spark plugs or carbon buildup, leading to poor ignition and unstable idling; fuel system problems such as clogged injectors causing fuel supply interruptions; transmission components like worn clutches that shake noticeably during low-speed gear shifts; and suspension or tire imbalance, which usually shows at high speeds but can also be felt at low speeds if severe. Ignoring these issues can accelerate wear, increase fuel consumption, and even damage the transmission, leading to higher costs. From my experience, I recommend car owners first perform a simple check—see if the spark plugs are blackened and lightly sand them to see if there's improvement. If that doesn't help, take the car to a professional shop for a thorough cleaning of the fuel system and throttle body. Regularly changing the air filter can also prevent impurity buildup and reduce the likelihood of shaking.