This requires checking whether the cylinder pressure of the second cylinder of the engine is normal, because the ignition coil, cylinder lines, spark plugs, fuel injectors and hydraulic lifters have all been checked, causing misfires in the second. The most likely possibility is that the cylinder pressure is incorrect.
The combustion of the mixture in the cylinder requires a sealed environment. The sealed environment is composed of piston rings, cylinder seals and valves. If any component is damaged or worn, it will cause poor combustion sealing. At this point, the mixture cannot be compressed and ignited, which will lead to cylinder failure.