The first time I cooked steak on my BGE the temperature rose very fast to over 600 degrees. Lately, however, the temp just creeps up very slowly, even with the bottom air vent wide open and no cap on the top. This is after I have removed the small pieces of charcoal from the charcoal chamber that might plug the air holes and raked out the ashes from below. I usually light the charcoal with 2 wax starter blocks. What's up??