Taqueria Nueve has earned a loyal following over the years, with its authentic Mexican menu and generally consistent execution. So when owners Billy Schumaker and Stephen Speiser branched out into the Pearl District this spring, there was reason to hope for another restaurant that evoked Mexico in an equally creative way. Unfortunately, despite cordial service and some successful dishes, they haven't re-created the magic.

With a touch of urban chic, D.F. (pronounced day-EF-fay) is named for Mexico's capital city, the districto federal. But the initials don't communicate anything about what to expect. The decor-a handsome, if generic, pseudo-industrial space with big windows, rich wood paneling and striking canvases-avoids Mexican clichés but gives not a clue about where in that country's vast and sophisticated cuisine the restaurant finds inspiration.

The menu is a grab bag of classic Mexican dishes, ranging from tasty little soft tacos ($3)-al pastor with pork and pineapple salsa, or with smoked fish and pico de gallo-to more expensive entrees like paella valenciana ($21) and a stew of oxtails in green chiles and dark beer ($17).

D.F.'s standouts echo the savory protein-rich plates at Taqueria Nueve, like tongue tacos, wild-boar carnitas and buffalo barbacoa. A daily mole special, an unctuous confit of duck leg ($17), was well suited to the complex, mahogany-colored sauce, though at that price some kind of side would have been nice. Bistec mexicano ($19) came perfectly medium-rare, with a smoky pasilla chile sauce worth licking off the plate. Yet other dishes don't pan out, like the whole sautéed fish drowned in bland sauce (around $20; price follows the market), or corn on the cob ($3) that showed up too cold to melt the butter and cheese that accompany it.

Four successive meals at D.F. were maddeningly inconsistent. The ceviche sampler ($12), a platter with three different preparations of marinated fish, used top-quality ingredients. But the flavors were never the same twice, sometimes balanced, at worst simply dull. Cockteles ($10-$15, depending on fish), the spicy seafood cocktails that Mexicans relish, tended toward sweet and flat.

Even familiar dishes can misfire. A pricey guacamole ($8) is described as containing serrano chile, onion, cilantro and lime, yet on two occasions all we could taste was avocado.

My favorite meal at D.F. was brunch, when the kitchen seemed to find its stride. Chilaquiles verdes ($9), strips of corn tortilla simmered in zesty green salsa, and huevos rancheros ($8) are first-class. On a sunny Sunday morning, with a good cup of coffee, breakfast at D.F. finally conjured up, if briefly, the pleasures of Mexico.