Jenn Air wall oven slow to heat

[roodney]

We’ve got a wall oven (J-A 8114p955-60) and it seems to be extremly slow to heat, and to heat it to 400 (for example) you need to set it about 100 degrees higher. It takes an hour to reach that temp. The element in the back seems to go on, and it gets to varying degrees of red-hot looking colors (not just a dim orange). We have had this issue since someone gave us the oven, although I think it is taking longer to heat than it used to. Any ideas? Thanks