"It's killing my business," said Mahmoud Sani, who runs a rental car business in Kaduna. "But if we don't buy on the black market, our cars will not be working but waiting in lines."
Even ordinary Nigerians are cashing in. Soldiers, police officers and government officials are among the people buying and reselling gas.
Last week, men driving cars with government license plates traded barrels of gasoline in the parking lot of the Public Enlightenment Department, an arm of the Independent Corrupt Practices and Other Related Offenses Commission.
The activities seemed to irk Mike Sowe, the head of the agency, which sponsors anti-corruption campaigns.
Noting that Nigeria recently helped Liberia and other troubled neighbors with their affairs, Sowe said: "In Nigeria, we export what we don't have -- democracy -- and import what we have -- fuel."
Government officials have ordered independent marketers to send all available gasoline to filling stations, not black marketers. But even Obasanjo said he knows that could be a difficult assignment.
"Even if you make police follow the tankers, they give the [officer] say 10,000 naira [roughly $80], and the police jumps down to say, 'Bye-bye.' They won't know where the tanker has gone," he said.
It was in that interview that Obasanjo, who has appointed a panel to probe the fuel shortages, said that one solution would be to raise gas prices. Because gasoline in neighboring Benin, Togo and Ghana can fetch up to three times the controlled price in Nigeria, marketers have been motivated to smuggle fuel to those countries.
But any effort to raise gas prices would be met with widespread protests, analysts say, noting that previous price increases triggered bloody riots.
Said Abudu, the motorist waiting to buy gas in Kaduna: "Obasanjo should focus on putting money in the pockets of poor Nigerians, not grabbing from the needy."