Characteristics of cylinder misfire:
Cylinder misfire means that there is no (proper) combustion taking place in a cylinder. This can be recognized by a shaking engine. At idle the engine runs irregularly, and when you accelerate you hear a vibration in the engine. At the rear, near the exhaust, a droning sound can also be heard. In this case the car also has less power. In most cases a warning light on the dashboard will turn on.
Possible causes of cylinder misfire:
Cylinder misfire is caused by poor or no combustion in the relevant cylinder. This can be due to a defective ignition coil, a spark plug that does not spark properly, an injector that does not inject correctly, or when the compression is not in order.
If a cylinder misfire fault has been stored in the computer (for example cylinder 1), the cause of the problem can be traced. Because cylinder misfire is often caused by a defective ignition coil (with an engine that has a pencil coil per cylinder), the coils can be swapped among themselves. Then swap the coil from cylinder 2 with cylinder 1, clear the fault, and then see which fault returns. If the fault has now moved to cylinder 2, replace the coil. If the fault remains in cylinder 1, there is another cause. Then remove the spark plug. If it is completely black and wet with oil, there is a leak somewhere (possibly at the valve guides). With a strong fuel smell there may be a fault in the fuel injector. If nothing else can be seen on the spark plug, swap it as well with cylinder 2.
If the fault is still present in cylinder 1, then the problem does not lie in the ignition. In indirectly injected engines with solenoid injectors, the injectors of cylinders 1 and 2 can then also be swapped. In engines with direct injection this is not a good idea, since the injectors are calibrated in the control unit. If the injector has been swapped and the fault has moved to cylinder 2, then replace the injector.
At the point where the fault is still present, it is advisable to measure the compression. It is possible that a valve is not sealing properly or that there is another mechanical problem causing a loss of compression. In that case too much air leaks away, which makes proper combustion impossible.