My oven heat sometimes turns off during cooking. The oven comes up to the proper temperture then once the element turns off it does not come back on as the temp. drops.

This does not happen every time. Christmas eve the kids did four loads of cookies. the oven worked fine. then they cheesecake, it took longer to cook than expected.

when cooking dinner. the food was still cold after half hour. then I saw the element glowining and dinner was cooking.

If you turn it off and turn it back on, the preheat light comes on but the element does not glow. if you turn it off and leave it alone for a few hours, it usually works fine when you turn it back on.