On automobiles they usually have the fuel cap as the breather. Note that from a practical standpoint, the other thing to consider if you’re simply trying to start the car but not actually drive it, is whether to use the gas tank at all. If your car is out of gas, it might not start. Pull the hose off and allow the gas to run out of the tank into your container until it is drained completely. Loosen the clamp on the end of the line that connects to the gas tank. Basically, no they won't. It will either be connected to an electric fuel pump, fuel filter, or to a hard fuel line that goes to the front of the car. i don't know about older cars but newer ones the tank is actually sealed and is under a vacuum. If your gas needle is off just a little bit, or if you’ve been driving around with your low fuel lite on for the past week or so, that might be related to your car not starting.