having trouble with my oven

HI!, I am having problem trouble shooting my oven, I press the Bake botton, set the temp, the oven on lights up and then the preheat light comes on, then the glow plug glows, but the gas does not come on… sometimes I can continue to press the bake light and and the gas will come on, the oven will preheat up to temp, the preheat light goes out and the oven and I think everthing is okay, but it takes 3hrs to bake a cake, I guess it does not keep the temp… at first I was haveing trouble with the bake light to come on, now that seems to be working but like I said it does not light or when it does it will not keep the temp. thank you for your help .:confused:

Chances are your oven sensor is out part number AP204835
Nat