[reliableapp]

Customer reported that gas oven was not heating to proper temp. Setting would say '475' but oven would be much lower than that - never reaching true temp. My first thought was that the sensor was bad as the ignitor was firing and flame appeared good, eliminating the valve issue. Replaced sensor.

Now, gas oven preheats just fine, then is able to maintain set temp for about 25 minutes. Then everything shuts down and temp drops significantly. Some other threads I've read indicate it could be ignitor is failing and thus not re-lighting the burner. Others indicate it could be the main control, which would be quite pricey for my customer. Not sure what or how to test to come up with the solution to this issue. Any help wwould be appreciated. Thanks!