Traeger Conundrum

Let's see who can figure this one out..

I have a Traeger that won't go above 400ish degrees. I've replaced the control unit, the induction fan, auger motor, temperature probe - basically every part. I experimented with the height of the chimney fan, made sure the hopper is clean. So... I basically reasoned that is wasn't getting pellets fast enough (they are brand new Traeger brand). I replaced the motor once... and it got to 450. I thought it was fixed... then it would top out at 400 again on the next go. I thought maybe the auger was stuck and burning out the motor.. nope. I replaced the auger motor again... and it immediately went up to 450. Then on the second go, it only tops out at 400. Someone please help me fix this Traeger from hell. Their customer service sucks, and my call to them was on hold for 45 minutes and had to hang up.