In a speech on Thursday night, he said Nigerians were seeing his economic efforts “bearing fruit.”

But outside the wealthy elite, all that means little to countless Nigerians. Mr. Daniel, for one, spends $200 a month to buy diesel fuel for his generator to keep his business going. He’s anxious to finish his medical degree but administrators at his school, and all public universities, keep striking for months at a time to agitate for better resources. His brother has an engineering degree but can’t find a job that pays more than the tailors earn at Mr. Daniel’s shop.

Mr. Abubakar, who has put economic issues at the center of his campaign, “knows what Nigerians need,” said Mr. Daniel.

Nigeria is bracing for what could be a tight election this weekend. Threats of violence loom.

In the northeast of the country on Tuesday, a convoy heading to an election event and carrying Kashim Shettima, a state governor, was attacked by Boko Haram, an extremist Islamist group which operates in the region. At least three people were killed, officials said. Many of the governor’s entourage fled into the bush after militants dressed as soldiers and riding in stolen military vehicles attacked, local news media reported.

The incident drew attention to another of Mr. Buhari’s 2015 pledges: to destroy Boko Haram. Far from being crushed, Boko Haram has recently been gaining strength.