CarsDirect identifies three of the most common problems that cause a car to switch off while a person is driving: broken or worn vacuum hoses, faults in the fuel intake system or an electrical wiring problem. Any one of these issues may cause a car to shut off randomly, but by following some basic troubleshooting steps, drivers might be able to pinpoint the source of the problem.
Vacuum hoses maintain the temperature and pressure around an engine. Over time, they become cracked and worn, which can cause the engine to stall. A vehicle's fuel intake system pumps fuel into the engine. If it gets clogged or starts to leak, an insufficient amount of fuel can cause the engine to shut off without warning. Finally, the vehicle's electrical system provides the spark necessary to ignite the fuel and power the car's engine. Faulty wiring can also cause vehicles to turn themselves off.
Sometimes, drivers can determine the source of the problem without a mechanic. They can check all the wiring and rubber hoses attached to the engine for leaks, cracks or other signs of extreme wear. They can also perform this check with the engine switched on to listen for the sounds of escaping air.