GE Oven shuts off during Bake cycle

[SIZE=1]Oven will start in Bake mode when cold and heat up, but unit shuts off sometime after it heats for a while. If the set temperature is low, say 200 F, it reaches this temp and sounds the ready beeps. If the set temp is high, say 400 F, it usually shuts off before reaching that temp. Today, it shut off at 285 F. Once it shuts off, it will not re-light until it cools completely down. If you light the broiler first, it burns OK, but if the oven shuts off, the broiler will not light. Checked both igniters and they are drawing proper amps. Checked 3 limit switches noted for this unit - the ones marked 157 and 158 are normally open and 159 normally closed in cold mode. When the oven shuts down, I checked the limit switches and all are in same mode as when it is cold. Checked continutiy across gas valve and it’s good. No codes. Any more ideas??[/SIZE]