I pass this along for the do-it-yourself folks out there. Couple weeks back, I was headed to work when I got an error code, and the engine started running very rough.
Took it in and it took a while for the technician to find the problem, but it was a very unusual breakage. What he found was that the tip of one of the two plugs in cylinder 3 had broken off (how does that happen) but stranger than fiction, the small broken piece had jammed into the second plug such that neither plug would fire.
Pretty simple fix, but I must admit in 40 years of driving I have never had a sparkplug BREAK, at least not the tip.