Why isn't my stove heating up to temperature?

It would help to know your model number.

Temperature Control Thermostat

The temperature control thermostat monitors the temperature inside the oven and cycles on the heat when the oven temperature gets too low. If the temperature control thermostat is not calibrated correctly, it won't cycle on the heat at the proper time. As a result, the oven temperature might be too high or too low. Due to its complexity, the thermostat is very difficult to test.

Temperature Sensor

The oven sensor works in conjunction with the oven control board to regulate the temperature. The sensor regulates the oven temperature by varying its resistance to electrical current as the oven temperature varies. As the oven temperature rises, the oven sensor creates greater resistance. If the sensor gives the wrong amount of resistance, the oven may not bake evenly. On some models, you can recalibrate the oven control up to 35 degrees Fahrenheit higher or lower. Refer to your owner’s manual for instructions on how to recalibrate the oven control.