Thanks! It ended up being a bad coil, once I got it out I could see a crack running all the way around, so I assume moisture had gotten in and caused a slow failure. Very relieved and happy to have the Disco running.

Fortunately, I was able to do the wires & coil pack without removing the intake manifold. I will be doing valve cover seals soon, but wanted to either confirm the truck as running or as bad as quickly/inexpensively as possible, so that was an interesting way to do so.