Oven heating unevenly

I have a Frigidaire free standing range that is not heating correctly. When using the bake option the top element does not come on, only the bottom one does. I have to turn the temperature way down so that the bottom of the food does not burn while the top does not cook. The broil option works however. It is my understanding that when using the bake option both elements come on until the oven reaches the selected temperature. Once it does the top one turns off and then the bottom one will maintain the correct heat. Is this correct? The model # is CFEF322CS1 The serial # is NF30714018 Can you tell me when this oven was manufactured? It has been in this house for 13 years for sure, but I do no know how long before that. Can you send me a manual/trouble shooting guide to see if there is something I should be doing or can do? Thank you, Karla