MARANELLO, Italy — A distemper was in the air last week in this immaculately manicured town of ocher and soft yellow masonry in Italy’s heartland, home to Ferrari since its fabled racing and production cars began rolling out of a rundown workshop here in the late 1940s. The disquiet is keyed to the imminence on Sunday of the Italian Grand Prix at Monza, 125 miles north of here in a wooded parkland that was once a playground for Italian kings.

The race, the defining event of Ferrari’s year, and the one that the company founder Enzo Ferrari coveted more than any other before he died at 90 a quarter of a century ago, arrives at a time when the summer’s heat has yielded to a gloriously temperate fall, with the grape harvest at local Lambrusco vineyards reported to be as good as any in years.

But because of the importance attached to the Monza race by the company’s executives, by the 650 staff members who work for the $250-million-a-year Formula One team, and by the company’s multitude of fans in Italy and around the world, September has often been, as company executives tell it in carefully muted voices, Ferrari’s most difficult month.

Ferrari’s years of competition, with their triumphs and their tragedies, have been accompanied by soaring passions — and bitter disappointments — among the vast numbers in this nation of 70 million who call themselves tifosi, fans who follow with what they and other Italians compare to the craziness once associated with bouts of typhoid fever. To them, the Formula One race at Monza is the apogee of the Ferrari year, and the event that more than any other can secure a winning Ferrari driver’s place in a history that includes 221 Grand Prix victories, 18 Monza wins and 18 world drivers’ championships.