Why Does My Car Shut Off by Itself While Driving? Causes and Solutions

Have you ever experienced your car suddenly shutting off while driving, only to restart immediately when you apply the accelerator? This can be a concerning and frustrating issue. In this article, we’ll explore the common causes of this problem and discuss potential solutions. Whether you have an older car with a malfunctioning engine immobilizer, a modern vehicle with stop/start technology, or a diesel with fuel-saving features, we’ll cover it all.

Causes and Diagnosis

Engine Immobilizer/Car Alarm Issue

One of the less common but significant causes of engine stalling while driving is an old aftermarket engine immobilizer or car alarm system. These systems can heat up and interfere with the engine's operation. If you’ve recently modified your car with such a device, it might be the culprit. To diagnose and fix this issue, you need to bypass the module. This involves re-establishing the connections to how they were originally set in the factory, effectively silencing the interference.

fix by bypassing the module meaning I connected it back to how it was connected in the factory.

High Resistance in Ignition Coils

In some cases, the issue could be due to high resistance in the ignition coils' primary winding. Ignition coils are critical for the car’s engine to function, and any malfunction can result in stalling. Replacing the ignition coil is usually the simplest and most effective solution.

fixing it by replacing the coil fixed the problemn!

Stopping and Restarting (Stop/Start Technology)

Interestingly, many modern cars are designed with stop/start technology to improve fuel efficiency and reduce emissions. This feature is commonly associated with vehicles made by Ford and diesel engines, such as those found in European cars like the Skoda. The system temporarily shuts down the engine while the car is idling, such as when at traffic lights. However, it may also cause the engine to shut off while driving, especially if the car is waiting in a queue.

It would frequently turn off when we stopped at a traffic light but started right away when I touched the accelerator. This is done to conserve fuel and reduce emissions.

Manufacturers’ Specific Features

Some car manufacturers, such as Volkswagen, preemptively disable the engine while idling to save fuel. While this is a commendable initiative to reduce emissions and save gas, it can be unnerving for drivers, especially if they are not familiar with the feature. The best way to understand if this is happening to your car is to refer to your owner's manual for specific instructions on how to override the default setting.

New VWs cut the engine when idling to save fuel. Your owner’s manual will include instructions on overriding this default setting.

What to Do Next

If you’ve tried the above troubleshooting steps and the issue persists, it might be best to take your car to a professional mechanic. Diagnosing such issues can be complex, as there are many potential causes. Without proper testing, it’s almost impossible to determine why your car is stalling.

No way to tell without seeing and diagnosing it. This is like asking online “why does my arm hurt sometimes”. There are a million reasons why and only through actual diagnosis can the problem be determined.

Conclusion

Engine stalling while driving can be caused by a variety of factors, from an old engine immobilizer to modern stop/start technology. Understanding the cause is crucial to finding and implementing the appropriate solution. If you’re unsure of what’s causing the issue, consult a professional mechanic. By staying informed, you can ensure your vehicle runs smoothly and efficiently.