sounds like a problem with your clock. when your clock fails it prevents gas getting to the oven but grill ect will work fine. check it hasnt accidentally been knocked onto automatic (if it has this function) if it is set to automatic reset to manual and that should do it. If it is already on manual you will need to change your clock.
appliance girl
July 2010
I can answer this question...
zenith 55 gas cooker, top gas is ok and grill, but no gas getting to the ov?