When I researched the V10, the plug issue was the only thing that comes up. Ironically, this is good. That means this engine is just about bullet proof, except for this very, very, very, very rare issue.
Did I mention this is a very rare problem. When a plug spits, it seems to appear on higher time engines and seems to be related to tune up / plug changes, specifically if the plugs may not have been torqued correctly and standard steel plugs were used (black colored base). This sounds like me. :-(
The mitigation is to use the nickle plated plugs (silver color base), use a small amount of anti-sieze, and properly torque the plugs to about 160 inch lbs. ( As a shade tree mechanic, I've never torqued a spark plug in my life, until now. I bought a small inexpensive torque wrench at Harbor Freight specifically to torque the plugs)
There is an inexpensive fix that an average DYI can do on the road, but does require a special tool set that can be bought or rented (this is not a standard helicoil fix)
As a temporary fix - If someone is concerned about this, I would recommend carrying one of the rubber spark plug hole seal tools. These cost about $20, you put it in the spark plug hole tighten the bolt, and the rubber seals the spark plug hole. Unplug the spark coil and the fuel injector for that cylinder, and continue your trip until you get home.
Although I was originally concerned about this. I have since not lost any sleep over it as I'm comfortable with the mitigation, and the fact that this is a very rare problem.