I've got a Kenmore electric oven that runs way hot. We've only owned it a few months (came with our house). I tried the self-cleaning cycle, and unplugging it/plugging back in, and it still runs hot. For instance, I just set it for 400 degrees, and when I check the temp on a separate oven thermometer, it's 525 degrees. The oven even has a calibration feature, and I have that set to the max at -30 degrees! Anyone have any ideas how to fix this--is it easily DIY or do I need to call a repair person? It's electronic, not analog. Thanks!