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Hi I'm Brian and I'm here to help. The two most common failure items for your furnace and with those symptoms are the pilot bi-metal switch (pilot must be replaced) and the gas valve (holding coil goes bad). It requires an volt/ohm meter to find out which has gone bad. To me this sounds more like the pilot switch. Click Here for a source for the OEM pilot switch. Click Here for a source for the OEM gas valve. Please know neither of these repairs are an easy repair.
Let me know if you have further questions on this subject. Otherwise, please remember to rate before leaving (3 stars or higher please!). Bonuses are always appreciated! Thanks for allowing me to help and thanks for using Just Answer!
Edit: I am just a tech here and have no access to the accounting side of things.
Hi Ed, Ok, your furnace doesn't actually use a "thermocouple". It uses a bi-metallic switch in the pilot burner to send permission to the gas valve to open the main gas valve. Click Here for a picture file of the wiring diagram for your furnace that I have annotated with help comments. You don't need to sign up for Drop Box to view it, just click the view file now button at the bottom. I hope this helps you diagnose your furnace. Note: you will need a volt/ohm meter to diagnose it. Let me know how it turns out! Please don't forget to rate your service with me when done.
P.S. you may need to zoom in on the picture, it is a little small :)