Engine unexpectedly dying while driving, stopping at red lights, or idling? A car stalling inspection identifies failing fuel pumps, dirty idle air control valves, vacuum leaks, and bad crank sensors.An engine stalls when the balance of air, fuel, spark, or mechanical timing is abruptly broken. When an engine dies specifically while coming to a stop or idling, the issue often lies in the idle airflow management circuit—such as a heavily carbon-fouled Idle Air Control (IAC) valve, a dirty electronic throttle body, or a sticking Exhaust Gas Recirculation (EGR) valve that dumps unmetered exhaust gases into the intake manifold at low speeds.