Our Natural gas oven will heat up to initial temp but will end up loosing temperature after a while. Sometimes it will go through several reheat cycles without any issues and then it will just stop turning the burner on. I have replaced the ignitor, checked ohms on both gas safety valves and the temperature sensor and they all checked out. What else should I be checking before I pay big bucks to have the repair man come in.
Model is
FFGF3049LS