Steven Manka, 40, was stopped Tuesday afternoon after running a red light in downtown Nampa, police said.
During the 1:41 p.m. stop, officers learned the car had been stolen the day before from outside a Nampa residence.
The car's owner had turned the engine on to warm it up and left the vehicle unattended with the keys inside.
Manka was taken to the Canyon County Jail and was charged with possession of a stolen car, driving while suspended, possession of marijuana and possession of drug paraphernalia.
The owner of the car was not cited for leaving it running while unattended," Sgt. Tim Randall said. A vehicle must be shut off and the key removed from the ignition, according to Idaho law.
Randall said the department wanted to remind people of the law and to make sure they stay with their vehicles when warming them up during cold mornings.
"The only time we've cited anyone is when a child has been left inside a car while it's running," Randall said. "For safety reasons, they should stay with their car."
A motorist cited for leaving a vehicle unattended could face a $90 fine, if convicted.