When you switch to a new coil beware of the burn in period. Always dial the power way low to start and work your way back up to where you like it over the course of the first tank. And the only problem I've had with stock coils is sometimes the o-rings on the bottom aren't big enough. My first mini flooded immediately and I forgot to check today when I purchased a new full sized nautilus. I'm still trying to figure out how to get the juice out from between the outside of the base and the ring that turns the airflow. You can see it when switching airholes. I swapped the ring with one off of an old coil that came in the package and it's working great. Never had a single issue with any of those ones. Just the ones that come with the tank for some reason.
If you've got a spare coil, they usually come with 2. Take a pic and show me. It should say BVC right on the coil if it's a BVC, but there's two kinds of BVC out there, the old school ones and the cotton ones, and I can tell which is which by the size of the holes in it. The more info we have the better we can hopefully help.