Abstract: Method for improving the operation of a knock-controlled internal combustion engine of the type having a fault recognition system for detecting failed knock sensors comprising the steps of incrementally shifting ignition timing in response to an appropriate output signal from the fault recognizer (assuming a failed knock sensor). The preferred method provides for monitoring engine RPM exceeding a threshold value, whereby the fault recognizer is activated thereby causing the ignition timing to be incrementally shifted (retarded) with an added safety margin to a preset anti-block value. Upon sudden reactivation of a failed knock sensor, the fault recognizer is deactivated and the ignition timing is incrementally shifting to the optimum knock-control value as controlled by the knock sensor. That is, the active knock sensor overrides the preset value, but the ignition timing override occurs incrementally. For RPM below the threshold value the ignition timing is incrementally set back to knock-free settings.