* City MPG: 17-20 mpg (miles per gallon) is a typical range.
* Highway MPG: 26-28 mpg is a typical range.
To get the most accurate MPG for a *specific* 2004 Chevy Impala, you'd need to know the engine size (3.4L, 3.8L, or 5.3L) and whether it has an automatic or manual transmission. The EPA's fuel economy estimates for that year would be the best source. You could also check the owner's manual for that specific vehicle.