Older Magic Chef oven won't stay stay fully lit after being ignited

I have an older Magic Chef oven, Model 3468XTW. The oven and stove generally work fine, but now the oven has developed an issue where in the Bake setting, the igniter will ignite the gas, and the entire tube will emit flame as it's supposed to, then it will die out to just the igniter flame. I replaced the igniter with a new one, and it makes no difference; after the initial igniting on the Bake setting, the flame will still shrink back to the igniter. The Broil option works fine on the...

Older Magic Chef oven won't stay stay fully lit after being ignited