Whirlpool oven does not work

My whirpool oven model sf315pegq does not work appropriately. We just moved to this place (6 months ago) and the oven never worked appropriately. it takes forever to turn on (sometime up to three hours) and it does not heat more then 325 F. I dont know what to do.

Hello Alketa. Based on the information you provided, it sounds like you may have a weak igniter. If the igniter is weak, the oven takes a long time to lite, and does not want to relite during the baking operation. Here is a link to the parts diagram and the part. Hope this helps. AP6007756 Manifold replacement parts for WHIRLPOOL SF315PEGQ0 GAS RANGE | AppliancePartsPros.com