The failure of just about any system on a car can cause stalling. The premier culprit for stalling problems is electrical failure, but there are a number of possible reasons cars stall.
Any stall condition is a result of some engine system that is not delivering air, fuel or spark at the right time or with the correct volume.
Sensor failures are a frequent cause of stalling. These sensors include the crankshaft position sensor, camshaft position sensor, throttle position sensor and oxygen sensor.
Fluctuations in fuel pressure also cause stalling, particularly on fuel injected cars. Possible causes may include a bad fuel pump, dirty fuel injectors or a clogged fuel filter.
If a car stalls at idle or under hard braking, the most likely cause is a bad Idle Air Control Valve. This valve controls airflow when the throttle is shut, and can become dirty or clogged over time.
Many new cars have a shutdown feature connected to the security system. Glitches in the antitheft system or auto door locks may cause random stalling or failure to start.