Pontiac has trouble deciding what it wants to be when it grows up.

For decades it had been designated the "excitement" division at General Motors, dedicated to the belief cars are more than just appliances. Pontiac with a capital P for performance.

But performance can be measured in different ways, apparently including high mileage.

So for 2009, Pontiac gets a version of the compact Chevy Cobalt called the G5 to be joined next spring by a four-door hatchback derived from the subcompact Chevy Aveo called the G3.

When G3 arrives, Pontiac will have four vehicles capable of 30-m.p.g. plus on the highway: Vibe at 32, G6 at 33, G3 at 34 and G5 XFE at 37.

Most don't associate high mileage with excitement. Pontiac, however, points out the newfound concern over m.p.g., rather than m.p.h., and how high-mileage offerings pull people into the showroom.

We tested the 2009 G5 in its special XFE edition-for extended fuel economy or extra fuel efficient. To be so, the 2.2-liter, Ecotech 4-cylinder comes with special variable valve timing calibrations to deliver off-the-line spunk and optimum mileage. Low-rolling-resistance, 15-inch radials milk more mileage while a spoiler adds a sporty touch.

The XFE is offered only with 5-speed manual, a slippery smooth unit with no rough edges. Honda long has offered the best manuals in terms of smooth operation and quiet. The XFE's takes it to a level higher.

The G5 powered by the Ecotech is lively though it stops short of lightning since it is designed primarily for mileage. The 2.2-liter, 155-horsepower 4 is rated at 25 m.p.g. city/37 m.p.g. highway, so you get membership in to the 30 m.p.g. club without having to pay hefty dues of the hybrid battery premium.

To maximize mileage, a dash light flashes to signal when to shift, though most motorists have other things to do than look for a reminder.

The G5 is offered only as a two-door coupe, and, as we've noted, there's no automatic for the XFE. The low-slung coupe roofline limits adult headroom in back, where legroom also is tight. The trunk holds lots of gear and looks more spacious than the rear seat.

Econocars typically concentrate on hammer-free ride at the expense of precise handling. G5 follows that formula, though if sentenced to the back seat, you might question how softly the suspension is sprung.

The G5 XFE starts at $16,275 with side-curtain air bags, air conditioning, AM/FM stereo with CD player, power locks/windows/mirrors (not seats) and rear-window defroster. Anti-lock brakes run $400, and stability and traction control aren't available. Power sunroof runs $750.

Read Jim Mateja Sunday in Rides. Contact him at rides@tribune.com.