i set the oven to pre heat @ 350 and minutes later the oven beeeps and preheated light is on, but the internal temperature is only 275 or so… I replaced the temperature sensor and no better, Does the broiler cycle to bring oven uo to temperature ???
Try replacing the bake ignitor at the bottom. It’s probably weak or going bad. If it’s ashy or white in color replace it and if you have an amp clamp test it and it should be pulling 3 amps or more if not replace it.