A mass-flow throttle for highly accurate control of gaseous supplies of fuel and/or air to the combustion chambers for a large engine in response to instantaneous demand signals from the engine's engine control module (ECM), especially for large spark-ignited internal combustion engines. With a unitary block assembly and a throttle blade driven by a non-articulated rotary actuator shaft, in combination with control circuitry including multiple pressure sensors as well as sensors for temperature and throttle position, the same basic throttle concepts are suited to be used for both mass-flow gas (MFG) and mass-flow air (MFA) throttles in industrial applications, to achieve highly accurate mass-flow control despite pressure fluctuations while operating in non-choked flow. The throttle, in combination with the sensors and ECM, enable detection of backfire events, with the throttle system further being enabled to take operative measures to prevent damage to the throttle components resulting from a backfire event.