I have an older furnace that I am trying to squeeze one more winter out before replacing. I came home tonight and the house was cold. Went down to the furnace and pulled the cover off and noticed the pilot was lit but the furnace had not fired on. If I blow on the pilot, the coupling sparks and the gas ignites the furnace turns on.

This is an older furnace that came when I bought the house 2 years ago. It looks like an automatic pilot system.

Is it a problem with the thermocoupling basically not telling the furnace to turn on the gas and light?

My guees would be that the pilot is not burning big enough to heat the bi-metal switch in the pilot. Use a screw driver blade and tap the pilot a few times to see if it does not burn better. If not you might have to take the pilot off and clean the orfice in the pilot.