Is the dryer short cycling ?? There is also a moisture sensor that can go bad.. Coils on top of the gas valve will also go bad.. They may hold the valve open 1 time & may not open the gas valve the next time.
I took the whole thing apart and cleaned the inside. Then started it up again. The flame comes on once. Runs for quite a while then goes out ( I assume because it has reached temp and the thermostat shut it off). After that it does not come on again. I can see the ignitor glow, but the gas does not come on. Does this mean it is short cycling? Solenoid is the problem?