If your gas oven is not heating there is a good chance you have a failed or failing oven ignitor. The Frigidaire 316489400 oven ignitor is a very common and typically easy to replace yourself part that can save you hundreds on a repair bill. Thrifty Appliance Parts carries these ignitors at nearly 90% less expensive than other retailers. This ignitor fits most Frigidaire CFGF366 models.
You can get yours here https://www.thriftyapplianceparts.com/316489400-oven-bake-burner-ignitor-for-frigidaire/