Hi, and thanks for reviewing the Timberline XL. Although pellets are the number one cause of temperature issues, please hold off on throwing them out until it can be confirmed that they are really the reason for your Timberline's performance. You can do a quick pellet test by breaking a few between your fingers and making sure that they snap cleanly in half, as opposed to crumbling, which is a pretty accurate indicator of their condition. And while maintenance can also be a factor, you likely already have this covered, especially on such a new grill. But as long as food is not in the grill during startup, airflow isn't being obstructed by pans close the interior walls, and the weather is not exceptionally windy, you shouldn't see more than a +/-25 degree variation in temperature. If none of the topics mentioned here are related to your situation, please give Customer Service a call at 1-800-TRAEGER. We might be missing something very basic that could make a big difference in the performance of your Timberline, and a quick phone call may be all it takes to get it corrected.