If your fuel economy is tanking, you could have a problem with your fuel system. Something as simple as a clogged filter can cause problems starting, engine hesitation, a rough idle, or even stalling. Telltale signs include your vehicle's failure to respond to the gas pedal or a seeming loss of power, even though it appears your vehicle is otherwise running well. The problem impacts your wallet, but there could also be safety issues. Why take chances, or throw your money away on excess fuel? Have your fuel system checked soon.