Vehicle Overview
Chevrolet's midsize TrailBlazer sport utility vehicle debuted early in 2002 as a five-passenger vehicle and was soon joined by an extended-length TrailBlazer EXT that offered seven-passenger capacity. The EXT offers an optional 5.3-liter V-8, an upgrade from the standard 275-horsepower, 4.2-liter inline-six-cylinder.

For 2005, a new version of the V-8 operates with Displacement on Demand technology, which promises up to 8 percent greater fuel economy. Under certain light-load driving conditions, the number of active engine cylinders is reduced.

Side curtain-type airbags are available for 2005. General Motors' OnStar communication system gains upgraded hands-free capability. An occupant-sensing system for the front passenger has been added. An MP3 player is available for the lower LS trim level, and the available navigation radio gets touchscreen upgrades. TrailBlazer EXTs come in LS and LT trim levels.

The TrailBlazer EXT is 207.8 inches long overall and rides on a 129-inch wheelbase. In contrast, the regular-length TrailBlazer rides a 113-inch wheelbase and measures 191.8 inches long. The EXT, at 77.1 inches, stands 2.6 inches taller than the regular TrailBlazer.

Ground clearance totals 8.1 inches. Wedge-shaped fender flares help give the TrailBlazer EXT a different appearance than its GM companions, the Buick Rainier and GMC Envoy. Running boards are available.

Seating for five people is standard in the regular TrailBlazer, but the seven-passenger TrailBlazer EXT gets a third row with a full footwell and 23.4 cubic feet of space behind the seat. Cargo space reaches 107 cubic feet when all the rear seats are folded. The second-row seat folds and flips forward to permit easier access to the rear.

Chrome accents have been added to the interior. OnStar is standard, and a backseat entertainment system with a DVD player is optional.

Under the Hood
A standard 275-hp, 4.2-liter inline-six-cylinder teams with a four-speed-automatic transmission. The optional 5.3-liter V-8, operating with Displacement on Demand technology, produces 300 hp and 330 pounds-feet of torque.

TrailBlazer EXTs are available with either two- or four-wheel drive, and the latter includes a two-speed transfer case. The Autotrac system's Auto 4WD setting transfers power to all four wheels automatically as conditions change.

All-disc antilock brakes are standard. Side curtain-type airbags are optional. Dual-stage front airbags deploy with varying force depending on crash severity.

Driving Impressions
Performance is a strong point, and the standard inline-six-cylinder engine does a credible job. Not only is engine sound barely discernible (except when pushed really hard), but road noise is also virtually absent. Acceleration has been stronger with the V-8 engine in earlier EXTs, but not by much, and the new Displacement on Demand V-8 isn't likely to perform dramatically better.

The seats are somewhat firm, and interior space is ample. Both hard-working TrailBlazers compete competently against the Ford Explorer and other midsize SUVs in passing power, ride comfort and handling prowess.