The couple was stopped at a stop sign on 31st Street at about 12:50 a.m. when the man came up to the car, police said.
The victim told police the robber held a gun to his head and said "Give me all your money or I'll blow your wife's head off," police said.
The 26-year-old victim handed over his cash, police said.
Police said they have a name for the suspect.
