Our GE oven is starting to fail on a regular basis. The initial problem was that it wouldn't heat to the set temp (generally, we have to have it set to 450F to get it to ~325F). The next problem is that the hot surface warning light on the cooktop stays on for hours after it's cooled down. Now we've started getting constant F2 errors, which usually occurred after the oven was off, but are starting to beep during heat-up.

I would guess that this is either the oven thermistor or the main board. Does this suite of errors tip off any of you dear readers?

Thanks!