It is installed in the air inlet hose between the throttle body and ... to the air and fuel going to the engine, helping your car burn gas more efficiently and cleanly. In our previous tests ...

To fill up the Civic Natural Gas, you connect a thin rubber hose from the dispensing pump to a snap-on receiving nozzle on the car. Then you rotate a valve and lift a handle on the pump.

If environmental impact were your only consideration when car buying, the choice between an electric vehicle (EV) and a gas vehicle would be easy. But for many buyers, there is also the very ...