I had a full bin of pellets from last season so I thought that had to be it so I replaced them to no avail. So I thought it had to be a leak or an obstruction. Gaskets all seemed to be OK. So I thought I would pull the fresh air intake and see how it ran with indoor air and I found that water was blocking the fresh air intake. I imagine most here were aware of this possible issue but it was new to me. Makes sense with the cold air coming through an uninsulated pipe into a warm house. I do remember reading about that now about 12 years ago. I will insulate it with insulatuing tape but still check it from time to time in the future. Hope this helps someone with a similar problem or this acts as a reminder to insulate.