other then a gas leak at the gas valve, the only thing i could think of is a bad ignitor, where it is getting weak, and cutting off, and then on, and the gas will come out for a little bit before the ignitor lights it. or, it could be the coils on the gas valve are not opening all the way, and you are smelling gas before it ignites. either one of these cases could be it, especially if you here a whoosing noise when the gas comes on. tom [url=]applianceeducator.com - parts[/url]