Brian,
I've had a 99 V70R for about a year and a half and have a fair amount of experience with the car.
From the sound of your description and the error code, it may be simply coincidental that the car is miss firing after the out of gas episode. It would be of benefit to try to determine if the spark plug fouling is due to fuel or oil contamination. The reason I'm making this point is that these cars react badly to poor maintainance, like infrequent oil changes in particular. You mentioned that you are a new owner. Any service records? If the oil wasn't changed at least at the recommended interval, or allowed to drop low at any point, the shaft and or seal assembly in the turbocharger may be damaged and leaking oil into the compressor, which then blows it directly into the combustion chamber, gets partially burnt and rejected out the tailpipe, fouling the spark plugs, the catylytic converter, maybe the oxygen sensor and everything else in its path. Some indicators of a bad turbo are oil on the inside of the intake piping and/or oily residue on the inside of the tailpipe. In my case there was even oil on the back window. Any smoke out the back during acceleration is a bad sign.
I hope it's something simple, but maybe this will give you some help. If it is an oil problem, the new plugs should at least get the car running again.