Changed out the Fan. Oven turns all heaters on to quickly get to temperature - the sensor probe is next to the broil heater - it quickly senses the broil element heat and claims a false oven temperature and "reaches" set temperature at the sensor probe. Changing the fan causes the air to circulate during this time - so the entire oven heats up. The Fan is supposed run in Bake mode during heat up. The Fan blade nut is a left hand thread - turn CCW to tighten and Clockwise to loosen - RIGHTY LOOSEY, LEFTY TIGHTY ..