Control system for an internal combustion engine and method carried out by the same

A control system (1) for an internal combustion engine is provided which comprises detecting means for detecting a discharge current (i2) flowing between electrodes (17a, 17b) of a spark plug (17) when a high voltage for ignition is applied to the spark plug, judging means for judging whether or not the spark plug (17) is fouled on the basis of the discharge current (i2), and inhibiting means for inhibiting the progress of spark plug fouling when the spark plug (17) is judged fouled. A method carried out by the control system (1) is also provided.