V-6 Sedan

• The 2006 Pontiac G6 V-6 Sedan came standard with a four-speed automatic transmission and a 16-gallon fuel tank. The vehicle delivered an estimated 22 mpg in the city and 32 mpg on the highway.
  
  

GT Coupe

• The GT Coupe featured the same transmission and fuel capacity as the V-6 Sedan. However, the car was slightly less fuel efficient, providing an estimated 21 mpg in the city and 29 mpg on the highway.
  
  

GT Sedan

• Like the other models with the 3.5-liter engine, the 2006 G6 GT Sedan included a four-speed manual transmission and 16-gallon gas tank. The car's gas mileage matched that of the GT Coupe, giving drivers an estimated 21 mpg in the city and 29 mpg on the highway.
  
  

GT Convertible

• New for the 2006 model year, the Pontiac G6 GT Convertible came equipped with a four-speed manual transmission. The car delivered an estimated 19 mpg in the city and 27 mpg on the highway, making it the least fuel-efficient in the 3.5-liter engine G6 line.