I've had the traeger silverton 620 pellet grill for a week. I've never owned a pellet grill before. I tried to smoke a pork butt last night. It was a 4.5 pound roast. It should have taken 4-5 hours. I put it on at 1 pm, I took it off and called it quits at 10 pm. Everything seemed to go alright through the cook. At 7 pm I thought this is taking way to long. I had the probe for the 620 in the roast keeping an eye on the internal temp. Around 9 pm the internal temp hit 170, then it started going down. Once it hit 162 I had enough, I pulled the roast off the grill and called it quits. What did I do wrong? Like I said, I'm a newbee. I googled how to smoke a pork roast, and I followed the directions to the t. I forgot the mention I had to different probes in the roast, one from the grill, the other one I bought after I bought the grill. They bought showed the same reading. I finally inserted a meat thermometer in the roast, It showed the same temp. Either I'm clueless, or something is wrong with this grill. If anyone has any imput on this problem please let me know, thanks.