We've all done it: set out for a long road trip, seemingly well prepared for the arduous journey before us: water, food, first aid supplies, communication devices, blankets, and passenger-entertainment all packed up for the increased safety and enjoyment of our journey. But. Somehow, the gas gauge needle got overlooked. And it's sitting rather low. You notice this just as you are approaching city limits. It doesn't make sense to stop for gas only moments after you've begun driving, but you're not sure where along your route the next gas stop will be. Do you gamble on this in order to save time and money? Perhaps the scenario isn't nearly so much in your control as the one just described: you may find yourself in the midst of a natural disaster with no access to fuel; how long will you be able to make it this way? Or perhaps the scenario is completely in your control: maybe, like Kramer, you are trying to defy your need for fuel by driving on empty as long as you possibly can. However you find yourself in the predicament of requiring fuel, but not having it, there are some things you should know about the importance of having adequate gas.
The very first thing you should know, especially if you plan to try doing this deliberately, is that you cannot really depend on your friends' experiences of doing this to determine how long or how far you'll be able to push your vehicle past its fuel consumption limits, no matter how similar your vehicles may be. A quick visit to TankOnEmpty.com will demonstrate this for you. Initially set up precisely for the purpose of comparing people's various experiences with this practice, it is possible to look up results by make and model of the vehicle in question. Doing so will show you that even cars of the same make and model vary greatly in this regard, and that the results of the entries made by various users offer no predictability at all. But if the thought of finding yourself stranded in a foreign place isn't enough of a deterrent to discourage you from this practice, consider this: driving on empty may actually turn out to be highly counterproductive for you. If your object is to save money, you may disappointed if you find yourself in a situation where it actually costs you more. There are actually some regions where, if you get caught being stranded as a result of doing this, you will be fined for making a hazard of yourself on the road.
Even more costly than a one time fine, though, is the amount of damage you are doing to your vehicle by not fueling it as needed. While not fueling up as needed may cause several forms of damage, the biggest concern in this regard is the effect of this practice on the engine. Without adequate fuel, the engine will draw air in instead, which will actually compromise the engine's ability to run. Once this mistake has been made, it isn't a simple matter of pumping the air back out: trying to do this can be very difficult, and even impossible in some cases. Additionally, you may be introducing rust to the insides of your car, starting with the gas tank, as driving on empty can cause moisture to get into it.
As with anything, there are sound ways to save on gas, and methods that should be avoided. Driving on empty certainly falls under the latter category.