If it feels like your oven is taking much longer to preheat than usual, it may be a sign that the power cord or power supply is not properly wired. Calling an electrician will help you determine if it is only a connection problem.  You can also contact GE Appliances to ask how they can help you with your stove. If you want to learn more about the normal preheat time of GE stoves, you might need to check out this page from their website.