For the 2009 model year, General Motors will extend the fuel-economy improvements seen in the Cobalt XFE to the Chevy Silverado and Tahoe, and GMC Sierra and Yukon.

The vehicles will reputedly return fuel economy improvements of 5 percent for highway driving and 7 percent in the city. They use a combination of enhancements including mechanical, aerodynamic, and mass-reducing elements.

Compared to non-XFE models that return 14 mpg city and 20 highway, the new XFE models will be rated for 15 city and 21 highway.

The Silverado XFE and Sierra XFE should emerge as the most aerodynamic full-sized pickups in the industry with their drag co-efficient measuring 0.412.

The XFE package will be offered on two-wheel drive models with a 5.3-liter V8 engine paired to a six-speed transmission.

Gary White, vice president and vehicle line executive for GM full-size trucks said, "Our pickups and SUVs are already the fuel economy leaders of their respective segments, but our engineers knew greater efficiency was achievable. We fast-tracked the XFE models to get them into dealer showrooms as quickly as possible."

GM debuted the Cobalt XFE in March. The vehicle employs revised gear ratios, engine recalibration, and low-rolling-resistance tires for an overall fuel economy improvement of 9 percent to 36 mpg over the regular model's 33.