Nnnnooooooo!!!! This can't happen to your engine Mark. It's gone so strong for so long!!

Is your mis-fire code is in cylinder three also? If so, that's very strange that two engines would have the same issue. I wonder what it is about cylinder three that's causing this.

I'm actually in the middle of tearing my old engine down to try and find out what was going on in cylinder three so I'll let you know what I find.

Not to freak you out, but my CEL started out innocently enough. It first popped up in Moab this year and didn't seem to effect anything. The VX would vibrate a little at idle with it in gear and my foot on the brake, but I didn't notice a dip in performance. As time went on the code showed up more and more, and the vibrations got worse and worse both at idle and cruising at highway speeds.

I had a compression test done with cylinder three coming back with zero compression. I then had a leak down test done (I think that's what they called it) where they removed the spark plug and forced air into the cylinder and then listened to see where the air was coming out. If they could hear air coming out of the intake then the intake valve would be bad or not seating right. If they heard air coming out of the tail pipe then the exhaust valve would be bad or not seating right, but if they heard air bubbling up through the oil (they listened at the dipstick) then the theory was something would be wrong with the rings, the piston or the cylinder itself that wasn't allowing the piston to seal to the cylinder.

During the test on my engine they heard oil bubbling through the dipstick which indicated an issue in cylinder three somewhere which is why I'm tearing the old engine down because it's bugging the crap out of me. Nothing was rattling around in the cylinder so maybe the rings broke apart but stayed in their races. I'll have a better idea in a few days if I can carve out some time to get into it.

Keeping my fingers crossed that yours is something easy to fix.