element works intermittent on simpson neptune oven how to fix?

Pull out elements on that model sometimes make a bad contact where they plug in & they spark & burn the metal. Pull element out & inspect the end of the element. If it is badly burnt away then you will have to replace the element. If only slightly black or burnt try rubbing a file lightly over to clean the contact surface. In extreme cases the connecting block will also be burnt and need to be replaced.

Lincoln Appliance NZ
September 2014