EW27EW55GS5 Electrolux wall oven won't maintain temperature

My Electrolux wall oven will heat up to about 50 degrees below the set temperature. (Used 2 thermometers for the average) It then begins loosing temperature and will not kick back on.(will drop below 100 degrees if set at 400)

I have replaced the oven temperature sensor with no change in performance.

I have now noticed that if set on "convection bake" it will preheat to within 25 degrees of set temperature and maintain the temperature within 25-50 degrees.

Any ideas? What's next, the control panel perhaps?

Thanks for any input.

via EW27EW55GS5 Electrolux wall oven won't maintain temperature
by Jagmaniii