If your car has become slower to accelerate, responds sluggishly to the gas pedal and is burning more fuel, the culprit may not be the gasoline or the injectors. Nikita Rodionov, technical director of the international auto service chain Fit Service, explained how worn spark plugs can simultaneously hurt performance and increase fuel consumption, according to infohub.kz.
A spark plug ignites the air-fuel mixture in the cylinder and must deliver a sufficiently powerful spark at the right moment. Over time, the electrodes wear down, the gap widens, carbon deposits appear or the insulator is damaged. As a result, the spark becomes weak or unstable, and the engine begins to misfire.
This shows up in the following ways: the car accelerates more slowly; the engine loses pulling power; jerking and vibrations appear; fuel consumption rises; the engine may be harder to start and may idle unevenly.
When misfires occur, one of the cylinders works inefficiently: fuel is consumed, but the engine does not deliver its usual output. The driver presses the gas harder, while the electronic control system adjusts how the engine runs.
According to the expert, in some cases consumption can rise by roughly 1–2 liters per 100 km. The exact figure depends on engine displacement, driving conditions, the number of faulty cylinders and the condition of the spark plugs.
Rodionov warns that unburned fuel can enter the exhaust system and cause the catalytic converter to overheat. A flashing Check Engine light deserves particular attention — it may indicate active misfires. In such a situation, continuing to drive can lead to additional damage and a more expensive repair.
At the same time, you should not rush to replace the spark plugs right away. Similar symptoms can be caused by: faulty ignition coils; damaged connectors or wiring; dirty injectors; air leaks; faulty sensors; low fuel pressure; mechanical engine wear.
That is why the ignition system and the engine should be diagnosed first. If a new spark plug quickly becomes coated in carbon or oil, a simple replacement will not solve the problem. Carbon deposits may be linked to an overly rich mixture, while oil may point to other faults.
Earlier, Kursiv Auto reported on the three most expensive components to repair in Chinese cars with internal combustion engines.