I once had a neighbor that was not only sweet but she was single. She couldn't boil eggs! Someone gave her a pit, and she cooked supper for me. OMG! Its was creosote residue! Since she was so sweet, I offered that evening after holding my breath while eating, to take the pit to the carwash and steam that sucker because I told her it was dirty.
I got most of the creosote off between the truck scrub brush and the hot steam cleaner. Drove around let it dry and brought it back. I offered to do ribs on it the next night. After the ribs she allowed that dirty on her pit tasted terrible and wanted to know if she should wash it every time she used it. I showed her step by step how to cook on it and from then own, I got Hot Krispy Kremes for breakfast for a month, but never another invite to cook for me.
Sometimes residue carries over.
Air or heat affects how fast or slow the wood smokes, too much fuel makes creosote. You may have to clean your pit to get the creosote out, its like pitch or tar. Then cut back on your wood when you smoke. You can make less fuel, smoke longer, by regulating the air, using a vent.
One other major sorce of creosote I just never think of it, green wood. If your wood is not seasoned it is a nasty smoke.
Lack of air should not be a problem, I cooked for years with a pit with no air at all. Too much smoke is.
Edited by Foamheart - 7/20/14 at 3:13pm