oven not working properly

I’m having a problem with my kenmore free standing gas range model 362.75481891. The stove and broiler work fine but the oven does not want to come on in a reasonable amount of time it take about 15-20 minutes, I think it might be the igniter valve but i’m not sure. Anyone have any ideas?

My Kenmore oven broiler would work but the oven part did not, we changed the igniter and it was working afterwards.