Oven Does Not Heat To Correct Temp

I recently installed a practically new (but used) GE oven. When baking, the oven temperature does not come up to the temperature set. The instructions for baking indicate the oven digital count will start at 100 and continue until desired range. This oven starts at 245 and will beep at desired range. When I open the door, the oven (set at 375) seems barely warm. Last night we tried to cook a pizza which should have taken 14 minutes but after 50 minutes it was not cooked. Can you advise me? After reading some of your forums, could it be the sensor? Thanks for your help.

AP2029062 its about 235 bucks plus shipping pretty cheap considering its a GE part ya just as well replace the sensor too. while you’re at it You can ohm out the sensor it should read about 1100 ohms at room temp

thanks for your information - I’ll check it out further when I get home.