2004 marked the re-return of the SS trim, the popular SuperSport package first seen over 40 years prior.

The engines on the standard and LS sedans remained the same: a 3.4-liter, 180-horsepower V6 with 21/32 mileage for the sedan, and a 3.8-liter, 200-horsepower V6 with 20/30 mileage for the LS.  The SS returned with a slightly louder roar, with a 3.8-liter, 240-horsepower V6.  Some die-hard SS fans scoffed at the idea of a V6 carrying the SS nameplate, but the six-cylinder engine has the rapid acceleration one would expect from a slightly larger engine.  The SS gets 18/28 mileage.

The 2004 remained popular for its large size, luxurious options, and strong engine.  Some have complained about frequent brake pad replacement, but most drivers have agreed that the value buyers get out of the 2004 Impala is excellent.