You are getting raw fuel into intake through carcoal canister.
It could be because of tank ventilation system failure.
If it does that always it would be fuel pressure regulator leaking fuel through vacuum line.

Any codes that are coming up?

No FPR on a 1999 with ME7 - but the overloaded EVAP canister is almost certainly it.

It moved to the rear passenger floor area, just in front of tire, in late 1998

Added year model to title per forum rules

You must find the reason why carbon canister is flooding...not replacing it.
Doing that you will not solve nothing.

This was happening to me when I bought my 2000 v70 a little over a year ago. Fuel (vapors?) fill evap system and flood the engine. I had to push throttle to the floor and crank for 10 seconds or so after every fill up to get the engine running and then, yes, keep rpms high for a little longer. The r...

P0445 is an emissions large leak. Usually the 'J' or 'L' pipes to the carbon filter. I believe on your car it is fitted under the passenger rear footwell or just behind it above the rear axle area. A bit of a swine to get to. The 'J' pipe comes from the carbon filter to the roll over valve. There is...

Could be a MAF connector failure.P0172 means that engine runs lean. Vacuum leak is another suspect. Next time before starting the car....open the hood and connect & disconnect MAF connector few times.After that...start the car and see if code re-appears.If so....i'll guide you for MAF connector ...