This Traeger will not hold temp. I have installed a new hot rod. Everything is clean and working as it should. Test today with new rod set at 180. Immediately went to 212 on panel and 241 on Redi Quick probe. Over the next few minutes it went from 215 down to 168 and back up again. At 168 went thru a smoke cycle. Finally turned it off at 215 with 252 on the probe. What to fix next? Thanks