Spark plug does look very trivial. Small form with a price range that is not so expensive, making it sometimes a little spark neglected. But, other than that, one of the fire on the cylinder axis header has considerable opportunities to make ignition engine so problematic.
Because the type and mode of each machine is different car, do not try to replace the spark plug with a spark plug manufacturers European manufacturers of Japan. Or maybe vice versa. Engine performance will be hampered, or worse still, the machine will actually stop working.
If malpractice plugs are continued, in the long run, the car will get worse with the damage. For the initial period, it may be started from the sensor, the ECU (Engine Control Unit) from less stable and also the components of the cylinder will work began to fall apart.
To restore the machine to normal, certainly not low prices. Because they have to get off the machine about half, it could just be spending budget reaches 5 to 10 million. Depending on the type of damage suffered. But, if you are a bit wary and careful, exact price will not be nearly so expensive.
Finally, it's suggestion. Keep cleaning your spark plug in order to make your vehicles run well.
