DETROIT — Pontiac, the brand that invented the muscle car under its flamboyant engineer John DeLorean, helped Burt Reynolds elude Sheriff Justice in “Smokey and the Bandit” and taught baby boomers to salivate over horsepower, but produced mostly forgettable cars for their children, will endure a lonely death Sunday.

Pontiac built its last car nearly a year ago, but the official end was set for Oct. 31, when GM’s agreements with Pontiac dealers expire.

The GM brand was advertised for “driving excitement.”

Pontiac brought Americans the Bonneville, GTO, Firebird and other venerable nameplates.

Sportier than a Chevrolet but less uppity than an Oldsmobile or Buick, the best Pontiacs, recognizable by their split grille and red arrowhead emblem in the middle, were stylish yet affordable cars with big, macho engines.

Pontiac’s biggest triumph was the GTO, developed by DeLorean, the brand’s rebellious chief engineer, in violation of a GM policy dictating the maximum size of a car’s engine.

The GTO was a hit, and the age of the muscle car had begun.

“When the muscle-car era was in its heyday, Pontiac was king,” said Frederick Perrine, a dealer in Cranbury, N.J., whose family sold Pontiacs since the brand’s founding.

“It put us through school. We were the house on the block that had the swimming pool growing up.”

For most of the 1960s, Pontiac ranked third in sales behind Chevy and Ford — a position now held by Toyota.

But in the decades since, Pontiac’s edge and high-powered image wore off. Repeated efforts in the 1990s and 2000s to revive the brand failed. Drivers too young to remember the GTO came to associate Pontiac with models like the DustBuster-shaped Trans Sport minivan or the Aztek, a bloated-looking crossover widely regarded as one of the ugliest vehicles of all time.

By early 2009, Pontiac had fallen to 12th place in the U.S. market, and its top-selling model was the G6, a sedan commonly found on car-rental lots.

For the most part, Pontiac’s final months generated no more excitement than its last few decades did. GM said dealers had fewer than 125 new Pontiacs in stock at the end of August, mostly heavily discounted G6s, but only eight of them were reported sold in September.

Pontiac sales peaked in 1973, when 920,000 were sold, and the ride was mostly downhill after that.

Pontiac fans lament that the brand finally got a few worthy models in its final years — the G8 full-size sedan and the Solstice sports car — but by then it was too far gone.