My Jenn-air oven has an intermittent problem maintaining cooking heat. Occasionally when I try to maintain heat the elements turn off and the heat is lost. Resetting the controls to the higher temp does not turn on the elements, and the oven must cool completely before I am able to reset it to a cooking temperature. This usually happens after >1 hr of cooking. I have replaced the clock and the intermittent problem still occurs. Should I replace the sensor? The fact that it is an intermittent problem makes me suspect the controls rather than the sensor. Any advice?