Reasons for the Geely Boyue shaking when accelerating in second gear: (1) During driving, the car engine shakes more severely than normal, and sometimes there is even a problem of failing to start once. This may be due to a dirty throttle, excessive carbon deposits in the fuel injector or intake tract. Under cold conditions, carbon deposits can absorb some of the fuel, and if the fuel does not completely enter the cylinder for combustion, it can cause unstable idling and difficulty starting. (2) When driving at high speeds to a certain speed, the steering wheel can feel noticeably shaky or jumpy, but this is not obvious at low speeds. In fact, there are many issues that can cause car engine shaking. Here, we first need to rule out abnormal shaking caused by engine faults, as engine faults usually also appear at low speeds. Solutions for car body shaking during acceleration: (1) If the car shakes noticeably during acceleration, you can first visually check whether the balance weights on the wheel rims are missing or if there is any obvious deformation in the wheel hub. If there are no issues in the above areas, then professional testing equipment is needed, as subtle deformations in the steering tie rod, suspension, or wheel hub are difficult to detect with the naked eye. First, check whether the left and right half shafts are bent. Then, disassemble and inspect whether the inner walls of the left and right inner CV joints are worn and have pits. In most cases, this is caused by damage to the inner CV joint. (2) Most modern cars have front-mounted engines and front-wheel drive, and their inner CV joints are often telescopic to accommodate changes in the relative position of the transmission drive terminal and the drive wheels during vehicle movement. Upon disassembly and inspection, it can be found that the inner walls of the inner CV joints, which frequently contact the outer shells of the needle roller bearings—i.e., the parts that transmit torque (stress points)—have developed pits. (3) During rapid acceleration, the engine and transmission assembly performs a slight lateral tilting motion, thereby changing the position of the aforementioned stress points. Since there is a certain angle between the axial direction of the half shaft and the inner CV joint, these stress points continuously change position along the axial direction during the rotation of the CV joint. The force generated by this change continuously pushes the car body left and right, resulting in the aforementioned "sifting" sensation. Replace the damaged inner CV joint or half shaft.
