Electric Convection Oven

My oven wont preheat to the temp I desire, could it be that the thermostat sensor is going, doesnt matter if it is on reg. oven, or convection oven. It will have some heat but not to the full temp

I have a Whirlpool Convection oven Gold Series, and when I preheat my oven to the temp I desire, it will only heat to a certain temp, doesnt matter if its the regl oven setting or convection oven, it does heat up, but not to temp, could it be the thermostate sensor??:confused: