Whirlpool oven

I am not clear on when to replace the igniter. The broiler turns on but the oven does not. If I see the igniter glow when I turn on the oven but I don’t hear the gas in the oven turning on, is the problem still with the igniter? When does the gas turn on, when the igniter reaches a certain temp? Is the gas combo valve possibly the problem?
Any help would be appreciated

It is Whirlpool oven model SF365PEGN0