Dryer Intermittently Won't Light

The first time you try drying the clothes, the igniter glows, but the unit fails to ignite the gas, there is the smell of gas, and then the cycle times out and the igniter shuts off. If you then open and close the door, and restart the cycle, the gas will usually light on the second attempt and function normally thereafter. But the first cold start is always no go. Any suggestions? Thanks a lot.
Ray