Fill up the gas tank before it hits reserve. Running the tank low creates two problems. The pump can overheat causing it to fail intermittently or outright and creating a very expensive repair, typically $500 or more. At any rate fuel pump service life will be shortened dramatically. This situation can also cause a check engine light resulting in expensive diagnostic time. Fill the tank when it gets down to a quarter full and save yourself some money. Ask Robert’s Automotive about how to use fuel efficiently and save your engine, or see our Car Talk & Tips page for more information.