During my last three cooks I have been experiencing a weird temperature thing. It seems like it is taking a very ,ong time to get the Egg up to temp and stable. The first few cooks were fine. Differences are the outdoor temperature (26 today) and the lump. I was using BGE lump now I am using Royal Oak (American made). At first I thought it was an airflow thing, and it may still be, but before this last cook I cleaned out all of the old lump and ash and when I filled the firebox I only used pieces that were larger than two inches or so to avoid the little bits cloggin the grate and firebox holes.
Here's what I am doing... I cleaned everything out and then filled the firebox half way up the ring with the largest pieces I could find in the bag of RO. The bag was brand new and had been stored in my garage. The lump was cold since the garage is near freezing, but I doubt that would change anything once things started burning. I used a BGE starter cube and had the dual function top off of the Egg and the bottom vent wide open. Once the starter cube had gone out I watched as the temps started to go up. Once the thermometer showed 250 (I was shooting for 325) I put the top on with the movable part of the top in the closed position but the daisy wheel fully open and adjusted the bottom vent to about 1 1/2 inches. On my early cooks this was around 325 - 350. Then i left it alone to prep the meat. I came back about 30 minutes later and the dome temp was still at 250. I open the top up about 1/2 inch and opened the bottom another 1/2 inch and watched and the temp climbed to about 275 and stuck. I opened thing up again and the temp climbed slightly, but not much. I used the wiggle rod in as many of the grate opening I could find and even moved the lump around from the top and the temp didn't move. I finally opened up the top 3/4 and the bottom all of the way and it took almost 45 minutes before the temp came up above 300 but stuck there. I tried to bring the top and bottom setting back to my "normal" setting but as soon as I closed the top even a little the temp started dropping again. I had time, so i just let it run almost wide open and finally, two hours after lighting the temps started moving again. Only at that point could I close thing up to the exact settings that I tried to start with and its been running at 325 for four hours without any adjustment needed.
So... Could I be seeing problems with airflow? If so, why did things go back to normal after a couple of hours when I didn' do any more wiggling or stirring? Could it be due to cold or damp lump and it took a while to warm up or dry out? Or could it just be lousy lump?
Thanks for any advice or thoughts.