The oven temp varies +/- 50 sometimes. Sometimes it is fine. It's undependable as is. Would replacing the thermostat AP2023067 be my best bet?
The issue with the unit having a large variation of temperature would most likely be caused by a faulty thermostat which would be part number WB20K10004.
Need to see the wiring diagram.
Answer Hello Phonesavanh, We will need your model number to help you with this. Please call 1-877-477-7278 or post your model number with a new question on the parts page. http://www.appliancepartspros.com/modelnumber_locator.aspx