My gas range is having problems. I purchased it used. The range top works find but the oven does not keep the temperature setting. I hear the ignitor clicking trying to light 3-4 times. I have to stop the baking function & reset it & it preheats trying to set the desired temp. It might take 2-3 hrs. of this to finish a 2 pies. We put it really high, 460-500, bake at 350. It has been a problem since I installed it about 6 months ago. I replaced the ignitor & the flame/burner unit together as they came as 1 unit. I thought this would clear the problem but it has not. Could it be the temp sensor not reading correctly.