It sounds like it might be a sticking gas control
valve for the oven or the hot surface igniter for the oven might be weak. You will need to turn the oven on and off completely several times until the problem happens. When I say completely I mean turn on the oven control and watch the igniter start to glow. Then when the oven burner comes on(should within a minute) shut of the oven control and wait for the igniter to stop glowing completely and burner to shut off completely. Then repeat the process again. If you try it about 10 times and nothing happens then the problem will be difiicult to identify. If you turn on the oven control and the igniter comes on but the gas burner does not then try giving the gas control valve(located in brolier/storage compartment) a tap with a wrench. If the burner suddenly comes on then the control valve was sticking. Try repeating the shut down/turn on process again. If it does not do it again you may have fixed the problem...if it does you will need to remove the igniter and test it with an ohm meter(should read
at least 500 to 800 ohms). If the igniter is testing good and glowing brightly then the gas control valve would be the suspected problem. And remeber to be very careful when doing these testing procedures so you do not hurt yourself.