Yesterday on my WSM I was doing some ribs at 225, and after I pulled them off to foil them, Top was off just long enough to pull the racks off. I could not get the temp back down. It stayed at 250 for the next hour. I use a stoker and had the other two bottom vents closed. Door is fairly tight, not a lot of space there. I even had the top vent 3/4 closed, but could not get it back down.

Any ideas?

There is nothing wrong with doing ribs at 250º or even higher. To me that is just a minor temp swing. Don't worry about small things. I usually do ribs between 250 and 275.

And I do them 75-100 degrees higher - but sometimes when that happens it's wood igniting. It's dried further in the restricted-air, low-temp environment created at the beginning of the cook; a draft rush can be enough to cause combustion. That's one reason I don't use fist-sized chunks.

Hard to say what caused it in your situation, Jeff, without having been there.