Got a Masterbuilt 340 gas smoker. Up til now, the temp in the chamber has been consistent with the dial on the front. Smoked a brisket last weekend, and while it came out fair, the oven thermometer hanging in the chamber would get no higher than 200, even when I cranked the dial to 300+. Took the hanging thermometer out of the rig this morning and put it in the kitchen stove, and it works fine. Is it possible that the unit is that flimsy that the doors won't keep the heat in anymore? Or is it a problem with the thermostat? The thermostat on this thing is mounted of the back about halfway up the chamber, and I have noticed it has a little buildup of grease, sauce, etc. Is it possible that this needs cleaning occasionally to keep it working right? I also see that the front has a warning about making sure the gas line is unobstructed. How could anything get in there to obstruct it? Besides, I lit the burner today, and watched as I fiddled with the temp dial on the front, and the flame increases the way i assume it is supposed to when I crank the dial. Anybody?