This paper looks at the nature and the length of the impact that prices and economic activity have on the demand for motor gasoline and distillate fuel oil in the United States. A general approach is presented and implemented to aid any energy analyst in gaining insights into the modeling activity. The results suggest that price changes affect the quantity demanded of motor gasoline and distillate fuel oil for as long as 2 years after an initial change while changing personal income has an impact for about 1 year.