I've got a Jenn-Air electric wall oven. The problem that i'm having does not occur every time that we use the oven (only about 30% of the time). When we set the temperature for bake (for example, today it was 350F), the oven will begin pre-heating. The element comes on and appears to look in good condition (no apparent dark or bright spots on it). The temperature will rise to about 230-250 F, then the element will turn off (goes dark), and the temperature will hold at whatever the temperature that it stopped at. If we leave it on for an hour or more, it will sometimes get there (to 350F or whatever the set temperature is). If i shut it off and restart the process, sometimes that will get it going again. I should note that if we're using the broil setting instead of the bake setting, then everything seems to work fine; but we only have "Hi" or "Low" settings. I'm guessing that i need to replace either the control board, or one or more thermostats, or the element... i'm just looking for some experienced input to direct me which is the most likely cluprit.