first off is anythig different like maybe a fan blowing at the back of the dryer that may have moved ind is blowing in the chamber direction? if not its probably a thermocouple or temp. controller.
This is a good place to start!
If it is not an external change in varibles, then it comes down to components.
Without knowing perticular brand/age of temp control, a guess would be an auto-tune
problem in the temp control which seems to have stabilized for now. Are all you control box fans working,
clean? There are alot of problems (intermentent) with all brands of machines now, because of HEAT! I am
gettings lots of calls with my machine just went crazy.... I am telling people to put $10 fans from your favorite box store, on your electrical control panel, to help lower heat. The controls of most electrical components,
unless stated, are about 125 degrees. Since our shops hover, in these temps, helps explain machines going
psycho!
Good Luck,
winston