Do you top off your tank at the gas station? Why that’s a really bad idea...

When that gas pump shuts off – your tank is full. 

Resist the urge to top off your tank with an extra squirt or two. Topping off the tank not only wastes money, it could mess up your car. That extra fuel will most likely feed back into the station’s pump through the vapor-recovery system – but you’ll still pay for it. You also risk causing that additional gas to evaporate into your car's vapor-collection system, which can lead to poor engine performance or trigger the check engine light.