Tenant's oven downstairs is very

Tenant's oven downstairs is very inconsistent. More often than not, oven will heat up to set temperature, then flame will die and oven will cool, but gas will continue to be emitted. Three tests this afternoon: 1.) Oven rose to 350° temp, then shut off. Very strong odor of gas throughout apartment. 2.) One hour later. Oven rose to 350°, then stayed there for about 20 minutes before shutting it off. 3.) After about a 45-minute cool down time started oven again. Fifteen minutes later oven says 350°, internal thermometer says about 320° and the flame is not burning, but you can hear motor (or fan?), running.