I have an inexpensive thermometer that hangs from the oven rack so it can be read without opening the door. My oven also stays within 5 degrees, but no more than 10 degrees of the set temperature. I have a Kenmore, but I think it is a Whirlpool product.depends on the thermometer being used, a regular oven thermometer it should stay within 5 degrees.
Looks like it is linear. My model is GFE461LVB 0. If the temp sensor is okay, then it may be a hysteresis problem with the temp controller.you haven't posted a model # but I'm just going to throw this out for reference. If you stove has a temp sensor and not a thermostat, the ohms readings for the sensor would be approx:
room temp 1000 ohms
300 degrees 1550 ohms
350 degrees 1650 ohms
400 degrees 1750 ohms
I will ohm out tomorrow. I can recalibrate +/- 30F and I know I can achieve the average temp to be at the set point, but, I want to know what temp variation is acceptable. My high to low is about 60F.I think you are over analyzing this. Here is how you check the temp of oven with a thermocouple probe type thermometer.
Preheat oven to 350 let it cycle 2 times
take temp reading at its high point then take temp reading a low point, do this twice.
average out the results: example oven cycles at high point of 360 low point 345 first reading
second reading 362 high 348 low add them all together for a total of 1415 degress divide by 4 = 353.75 degress. That would be dead on balls accurate. You should be able to recalibrate your electronic control + - 25 degrees. If its over 25 degrees off set temp then ohm out sensor with the measurements I posted before.