Two days after an apparent assassination attempt against him, former President Donald J. Trump showed few signs on Tuesday that he would shake up his approach to campaigning.

At a town hall in Flint, Mich., for his first campaign event since the Sunday incident, he made grand promises to restore auto-making jobs to the state, the heart of the American auto industry, as he gave long-winded, often meandering responses to only a few questions.

To the extent that Mr. Trump was focused, it was on repeatedly vowing that his tariffs would revitalize the auto industry in Michigan, a crucial battleground state, and that a Trump loss in November would be catastrophic — referring to such an outcome as a “tragedy.”

Using the dire language he often uses to frame this election, he said if “we don’t win, there will be zero car jobs, manufacturing jobs.”

“It will all be out of here,” he said.

Speaking to thousands of supporters in the Dort Financial Arena in Flint, he also insisted vaguely that his tariff proposals would be enough to reverse a decades-long decline in the American auto industry and bring “so many auto plants” into the state if elected.