My initial setup of my
Camp Chef did the same thing to me. The instructions said to set the rain cap to 1.5 inches or something like that. I called them and they said that was wrong and to lower it to approximately 3/4" Now that's the height of the jam nut in relation to the top of the all-thread rod going into the rain cap. That stopped the radical swings, but it still wasn't all that good. The original controller was in 25 degree increments and that's about the swing I got after fixing the rain cap height. Once they came out with a new PID controller to replace the ortech style my temp control is far better. Having typed all that, I'm pretty sure I posted a thread about this a few years ago...