i agree its the valve. had to replace lots of them problem is in the switch. jiggle it and you will probably loose flame.
At HVAC Site we cater exlusivly to professional contractors who make their living as a contractor. Knowing that many homeowners and DIYers are looking for a community to call home, we've created www.DIYChatroom.com DIY Chatroom is full of helpful advices and perfect for DIY homeowners.