Diagnosis
Unburned gas escaping during the ignition cycle. Likely a weak igniter taking too long to light, allowing a small gas puff, or a misaligned burner letting gas escape before ignition.
How to Fix It
First, inspect the oven burner assembly.
1. Turn off gas and power.
2. Remove oven floor and burner cover.
3. Check that the burner is seated correctly over the gas orifice and that the igniter is positioned close (about 1/4 inch) to the burner ports.
4. Try lighting the oven. Watch through the window. If the igniter glows for more than 90 seconds before lighting, or the flame starts away from the igniter, the igniter is weak and needs replacement.
If That Didn't Work
There could be a small crack in the oven burner tube. This requires a visual inspection and replacement of the burner assembly.
Heads Up
Any gas smell is serious. If the smell is strong or persistent, turn off the gas supply, ventilate the area, and call a professional. Do not use the oven.