Crank up the heat to 275-300F at grate level, your proteins will cook appropriately. Using a "target temp" of 235, if your thermo is off by 15F, you could be cooking at a 220F grate temp. This is going to take forever and a day to cook large hunks of meat. Sounds like another victim of the 225F myth. Also try not to peek (open the cooker), let the low pressure cooking system do its thing.