While smoking my summer sausage this weekend, seemed like it took forever to get the last 6 degrees in the sausage. I hit 149 and pretty much stayed there for over an hour. I finally took some card board and covered the 4" vent pipe completely. It has built-in damper but there's still a pretty good gap around it. I bought the pipe/damper from Allied-Kenco. The internal temp then started to rise again and I finally got it to 156. The sausage hangs directly under the vent. Could a cold air draft be coming down thus creating a cold spot in the center? Maybe I need a baffle under the vent? It was in the single digits when I started and temps never got over 20 so that could be part of the problem but the insde temp of the smoker was 180-190.