It's probably on the threads due to the oil running down as you are unscrewing it. A single cylinder misfire would not likely cause stalling, and the misfire monitors on these OBD-II cars are pretty good. If that were the problem I would expect you to have a Cylinder #3 misfire code (P0303). The cylinder nearest the firewall on the passenger side would be cylinder #3. Does the electrode of the plug suggest that it's not been firing? Also, the plug and head will hold quite a bit of heat. If it takes 3-5 miles for the plug to heat up enough to act up, it won't cool in just a few seconds and go another 3-5 miles.
-Rod