I replaced both igniters (WP part #s 8191123 and WP8054129) but no luck. I should've tested mine first for continuity b/c I learned it's a pretty easy test with a multi-meter. Next, I tested the high-limit thermostat fuse (WP part # 8300802) b/c this often blows, especially after using the self-cleaning function. This part also tested fine so APP suggested the gas valve (part # WP9763716). This is the part that fixed my oven. I'm not technical so I didn't understand how the burners could work but not the oven bake/broil if it was a gas safety valve, but that was the case for me. My guess is that the gas safety valve part actually has 2 valves and the one for the burners worked but not the one for the oven.
The hardest part of the installation was pulling my slide-out oven away from the wall, working in a tight space, and pushing it back in place. The actually gas valve itself was a pretty straight-forward replacement.