Driving your car, everything is going smoothly. Then it begins to rain. Your automobile starts to splutter and cough the next thing you know. What is happening?

This can happen for a number of reasons, but the most common cause is water getting into the gas tank. This happens more often than you might think. How does water get into the fuel tank? It comes from condensation in the engine and from leaks in the fuel system.

When heated air collides with a cold surface, condensation occurs. As warm air enters your vehicle's engine, it meets up with cold metal surfaces like water jackets and cylinder heads. This causes some of the water to condense into droplets, which then drip onto other parts of the engine.

These drops land in places where they can easily find their way into your fuel system: under the valve covers which are located directly above the cylinders, inside the air intake manifold, or even behind other components, such as an exhaust manifold.