oven turns off by itself doesnt reach set tempature

Hello, have a GE gas oven set to bake @ 350 starts to preheat will only reach 250 and oven shuts itself off. Try it again same thing, shuts its self off at 250 as if you hit the cancel button. Clock stays lite up. I tried self clean cycle and it seemed to work ok, door locked, fan started running. I stopped it before it got too hot so I could get the door to unlock without having to wait for the oven to cool down. Tried the broiler burner
, it seemed to be working ok. Tried bake again at 350 and it reached 350 with out shutting off. I thought great its working. Tried bake the next day same problem, oven shuts its self off at 250 wont go any higher. Is there some special setting or feature on this oven causing this???? Made sure the keep warm setting was off.