Why is the oven temperature incorrect?
The oven temperature control is usually controlled by a thermostat that uses a capillary and liquid filled bulb. When the bulb's liquid gets heated up, it expands and puts pressure on a diaphragm which opens and closes a switch that controls the gas to the burner. Just set the dial to what you need the temperature to be. Over time, it is possible for your thermostat to lose its calibration. Sometimes, the thermostat sensing bulb comes loose from the holder. If it is out of place, the thermostat may be getting faulty readings. If this is the problem, re-aligning the bulb properly will take care of this problem.
Digital display models use a sensor to control temperature. If this is faulty, replace it. Other ovens use a mechanical system to control the temperature.
On many models, you can adjust your oven thermostat using a small screwdriver. The adjusting screw is located on the thermostat valve stem. Remove the knob and you'll see the screw underneath it. You want to turn the oven on and run it through at least two cycles while watching a calibrating thermometer in the oven for high and low temperatures. Adjust the screw as necessary to fine tune the temperature.
Some models don't have an adjustable thermostat, and you will have to replace the thermostat if you want to resolve the problem.
The oven sensor: works with the oven control board to regulate the oven temperature. If there is an oven temperature problem, this sensor might be defective. The sensor can be tested by using an ohm meter. As temperature rises, the resistance measurement also rises. The manufacturer of the oven sensor determines the correct resistance, Oven temperature problems can be caused by other things, but this is one of the common causes.
Beware on some models now most of these ovens they are electronic and they are integrated into the control itself
some different sensor ohm readings at room temp. approx 16 ohms at room temperature and at 350?F it is 29~33 ohms.
The reason for my free advice is GOD is good!