Q: Car stalled while driving - 2006 Kia Optima

Hi and thank you for writing in. Most likely what is happening here is that, by over filling the gas tank, you allowed gas to enter into the gas tank breather tube. As you start driving fuel is being drawn out of the gas tank. With the breather tube choked off by gas, this will not allow air back into the tank to equalize the pressure. Your electronic fuel pump is not strong enough to overcome the negative pressure and basically you are running out of gas. As soon as your engine dies the gas that was in the breather tube is allowed to enter the gas tank which clears the breather tube. At this point the gas tank pressure is back to equal and you will be able to start your engine because the fuel pump can supply gas once again. Best cure for this issue is to be extra careful to overfill your gas tank. If this problem continues while you have less then 3/4 of a tank a fuel system check will need to be perform a car stalling test to isolate what is causing the engine to shut down. If you would like to have this done, a qualified professional from YourMechanic can come to your car’s location to perform this service for you.