Base Sedan

• The standard engine for the 2004 Chevrolet Impala is a 3.4-liter V-6 paired with a four-speed automatic transmission. This engine produces 180 horsepower at 5,200 rpm and 205 foot-pounds of torque at 4,000 rpm. This car has an EPA rating of 19 mpg city, 29 mpg highway and runs on regular gasoline.
  
  

LS Sedan

• Impalas featuring LS trim are equipped with a 3.8-liter V-6 engine paired with a four-speed automatic transmission. This sedan's output is at 200 horsepower at 5,200 rpm and 225 foot-pounds of torque at 4,000 rpm. The 2004 Chevrolet Impala LS runs on regular gasoline and gets 18 mpg city, 28 mpg highway.
  
  

SS Sedan

• The performance model for the 2004 Impala is the SS sedan, powered by a supercharged version of the 3.8-liter V-6 engine. Paired with a four-speed automatic transmission, this engine is rated at 240 horsepower at 5,200 rpm and 280 foot-pounds of torque at 3,600 rpm. According to Motor Trend, this model goes from 0 to 60 in 6.8 seconds. This car requires premium fuel and obtains 17 mpg city, 26 mpg highway.