A driver leaving a KFC in Broadmeadows pulled a gun out and shot at another car in an "outrageous" case of road rage, police said.

Broadmeadows Detective Sergeant Peter Griffiths said a small red car was leaving the KFC on Pascoe Vale Road at 7pm on Monday when it almost crashed into a Nissan Patrol travelling north.

Angered by the near collision, the driver in the red car sped up alongside the Nissan Patrol and gave the shocked 20-year-old Roxburgh Park man behind the wheel a barrage of abuse.

The Nissan turned west into Somerton Road and into Ravenhill Boulevard, with the road rage driver following behind.

Detective Sergeant Griffiths said the angry driver then overtook the Nissan Patrol, pulled over and got out of the car with a gun and fired it at the Nissan, which was still moving.