Moral of the story: Never take a misfire code P030(x) for granted. Aka keyswitch "code 43" The fix can be as simple as rerouting the plug wires so they don't arc between them (TSB 18-48-98), or it can be difficult and very-very expensive.
For those who recall me fighting a P0307 (cyl #7 misfire) code on my 97 Ram 1500 (80k miles) for the past 19½ months, I got the truck back and it is finally fixed, albeit $1946.71 later - and that's in U.S. dollars for any of you Canucks who may be wondering :-)
Actually the grand total is at least $350 more than that if we factor in all of the prior diagnosing and "attempts" over the past 19½ months by independent shops and my own shadetree work. Alas none of these efforts had any long-lasting effect. After many frustrating months of trying this and trying that, and the problem always coming back, the bottom line was it had to go to the dealer.
Though far cheaper than a new truck, it was a tad expensive, but a couple hundred less than the original estimate.
The fix: Two complete -new- fully assembled cylinder heads @ $353 apiece Top-end overhaul gasket set $144 (for gaskets? Holy tomatoe!) both O2 sensors at $102 each (! again - kinda proud of these) New cap, rotor, plugs, ignition wire set, T-stat, coolant, oil, etcetera, etcetera, etcetera, etcetera and ETCETERA Total parts $1275.21 total labor $ 671.50 (8½ hrs @ $79)
12-mos/12,000 mi warranty on the parts & labor (yes both, I did ask) Free loaner car for 4 daysNice to have "ole Nelliebelle" back home.