Oven temp will not always reach set point, sometimes off by 50 degrees. Then again,sometimes it is o.k. ????
You will want to check the oven sensor to make sure that it is around 1090 ohms at room temperature. If the resistance is not correct then replace the oven sensor. Also check the wiring between the control board and the oven sensor to make sure that there is no damage and has continuity through it.