Is my Furnace gas valve going bad?

[VERN in IL]

Coleman Presidential II

It has a pilot light....

Every now and then very randomly the furnace starts to WHOOOSH, it seems to run just fine during the heating cycle...

When it is time to turn off, everything is fine, the blower shuts off, however,sometimes the WHOOOSH keeps going, and then the furnace cycles on off on off, still WHOOOSH sound.

The only way to stop the WHOOOSH is go to the thermostat, and select OFF.

The WHOOSH stops, and I can turn the thermostat back "AUTO/ON" and it works just fine!

I suspect my gas valve is sticking open, pretty sure the WHOOSH is gas rushing into the chamber, any ideals?

Sounds to me like if you manually kill the power to the furnace from the thermostat the furnace quits short cycling . Maybe a thermostat problem . I would check the low voltage thermostat circuit , limit switches , etc . with a multimeter before condemning the gas valve .

[VERN in IL]

This does not explain the WHOOSHING, the thermostat could be bad, it only has a two wire hookup..

The cycling is caused by the WHOOOSHING, it only cycles when it starts randomly WHOOSHING, like as if the Propane tanks regulator is increasing the pressure, by a lot.... and it's not killing the flow of gas to the flame spreader. The WHOOSHING is only happening while the unit is active.

Problem is, this only occurs like once a week or two, cannot recreate the problem, it's all random.

Deleted

[Clod Kicker]

During the whooshing sound put a multimeter across the terminals on the gas valve and see if there is 24vac there. See if it there intermittently and in time with the flame. Turn off the power switch and make sure the flame goes out.
there could be a loose wire in the control (24vac) circuit, or a malfunction in the tstat itself. If you have an electronic circuit board, you need an analyzer to check them out, and its best to call a serviceman. The analyzers can go upwards from $250 to buy...