What is going on with my wood stove??

[jramstead]

Actually mine has started to do this also. I have a blazeking princess.
Could the catalitic converter be going bad. Ive had mine for about seven years.

 

[Arbonaut]

Freezing and Thawing? Your masonry chimney can move independently from the house. It could rock and jar something loose. Are you near coal mines?

 

[steved]

he has an epa stove, so there is always oxygen available.

Just for the record, I have an "EPA stove" and can make it do exactly what the OP is experiencing...

I got a frantic phone call from my wife when it first did it...told her to open the draft up, and it stopped immediately. I've had it happen a couple other times...what is happening in my case is my stove has both a manual and automatic draft; and the automatic will pinch back even further if the stove is hot, making it difficult to set the draft at times. Simply opening the draft (even slightly) will make the issue go away.

Seeing this process happen through a glass stove door is even more, umm, entertaining...