What are the causes of vehicle shaking?
3 Answers
Vehicle shaking can be caused by: 1. Excessive carbon deposits. Severe carbon buildup in the engine cylinders can lead to clogged spark plugs and valves, resulting in shaking during idle; 2. Fuel supply system failure. Unstable fuel pressure can cause fluctuations in the air-fuel mixture concentration, leading not only to shaking but also unstable idle; 3. Worn engine mounts. If the vehicle's engine shaking becomes increasingly severe without a corresponding loss of power, it may be due to deteriorated engine mounts; 4. Misfiring cylinders. If the ignition coils malfunction or spark plugs fail to fire for any reason, the vehicle will exhibit shaking.
What I fear most while driving is encountering unexplained car body vibrations. Last week, when I was driving on the highway, the steering wheel shook so badly it made my hands go numb—turned out the front wheel balancing weights had fallen off. Another time, while waiting at a red light, the entire seat was vibrating, and it was later diagnosed as worn-out engine mount bushings. Bulging tires or deformed rims can also cause the car body to shake at low speeds, and uneven brake discs can lead to sudden vibrations when braking. If the car jerks like it's shivering during rapid acceleration, it's likely due to faulty spark plugs or ignition coil issues. My advice is not to ignore these problems. Last time I neglected engine vibrations, it ended up costing me over two thousand more to replace the transmission mount.
Having seen many shaky cars in the repair shop, common issues fall into several categories: First, intake manifold leaks causing an overly lean air-fuel mixture—this makes the idle shake like a massage chair. Second, throttle body carbon buildup causing sticking, leading to jerky acceleration. Third, collapsed engine mounts, transmitting engine vibrations directly into the cabin. Last week, a car shook violently in D gear, even the gear lever wobbled—turned out to be a broken transmission mount. More dangerously, brake shudder: one owner said the steering wheel vibrated like it had a motor when braking at high speed; upon disassembly, the brake discs were found worn into wave patterns. Such issues can usually be pinpointed by reading data streams with a diagnostic tool and performing an undercarriage inspection.
