A control system and method for obtaining combustion stability in an internal combustion engine including an accelerometer mounted on the engine for detecting engine block vibrations and an engine controller for processing an accelerometer output signal indicating engine block vibration intensity to measure cylinder combustion energy, the energy measurement being correlated to other combustion parameters including indicated mean effective pressure (IMEP), the controller developing a control signal that may be used in a closed loop fashion to adjust engine variables including exhaust gas recirculation, air/fuel ratio, and spark advance, thereby adjusting the engine operating characteristics to achieve optimum combustion energy.