Characteristics of Cylinder Misfire:
Cylinder misfire means that there is no (proper) combustion occurring in a cylinder. This can be recognized by a shaking engine. Idle, the engine runs irregularly and when accelerating, you can hear a vibration in the engine. Also, at the back of the exhaust, a roaring sound is audible. In this case, the vehicle also has reduced power. In most cases, a warning light will also illuminate on the dashboard.
Possible Causes of Cylinder Misfire:
Cylinder misfire is caused by poor, or no combustion in the relevant cylinder. This can result from a defective coil, a spark plug that sparks poorly, a faulty injector, or when the compression is not in order.
If a cylinder misfire fault is stored in the computer (for example, cylinder 1), the cause of the problem can be investigated. Since cylinder misfire is often caused by a faulty coil (in an engine with a stick coil per cylinder), the coils can be swapped among themselves. Swap the coil from cylinder 2 with cylinder 1, erase the fault, and then see which fault reappears. If the fault now occurs in 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 leakage present (possibly at the valve guides). If there is a strong fuel smell, there may be a fault with the fuel injector. If nothing further is visible on the spark plug, swap it with cylinder 2 as well.
If the fault still remains in cylinder 1, then the problem does not lie with the ignition. In indirectly injected engines with solenoid injectors, the injectors from cylinder 1 and 2 can also be swapped. In direct injection engines, this is not advisable as the injectors are learned in the control unit. If the injector has possibly been swapped and the fault has moved to cylinder 2, replace the injector.
If the fault is still present, it is advisable to measure the compression. A valve may not be sealing properly or there is another mechanical problem causing compression loss. In that case, too much air leaks away, preventing proper combustion from occurring.