You may need to replace the Spark plug:

·The fuel mixture concentration of the car is too high, causing unburned parts to accumulate on the spark plug and form carbonization.
·The electrode distance between spark plugs is too large.
·The oil in the car enters the cylinder.
·The quality of the oil used is poor.

Sequence of replacing spark plugs:
1.Before removing the spark plug, the correct spark plug model must be selected based on the vehicle model, engine, etc.
2.During installation, it is necessary to ensure that gloves or hands are clean and tidy to prevent oil stains from adhering to the surface of the spark plug insulator, as oil stains can conduct electricity under high voltage.
3.When installing, use a spark plug sleeve to slowly deliver the spark plug to the spark plug socket to avoid deformation of the spark plug side electrode and change of the spark plug electrode gap.
4.Using a torque wrench or tightening spark plugs according to relevant regulations, excessive installation torque or deviation of the spark plug sleeve axis from the spark plug axis can damage the ceramic insulator and cause engine shaking, side electrode erosion, and center electrode ceramic body fracture. If the installation torque is too small, it can cause air leakage and overheating.
5.After the installation of the spark plug, ensure that the spark plug is reliably connected to the high-voltage wire and ignition coil.
6.To align the threads, especially if the spark plug hole is deep, special tools need to be used. If there is a significant resistance when screwing in, blind force should be avoided to avoid twisting the threads and causing damage.

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