Contrary to popular belief, sugar does not dissolve in gasoline. If sugar is poured into a gas tank, it will sink to the bottom and remain in its granular state. Sugar can clog the fuel filter or fuel injectors if there is too much of it, which can cause problems like stalling and power surges. However, sugar in a gas tank is not likely to cause long-term damage to the engine or completely ruin it. The worst-case scenario is that the fuel filter may need to be replaced or the gas tank may need to be emptied out. Therefore, it is a nasty trick that can end up costing money, but it is not a serious threat to the engine. If someone suspects that sugar has been poured into their gas tank, it is recommended to take the car to a mechanic to have it inspected and repaired.