I have been having an issue with a 1998 v70 base. First symptom was a feeling like the transmission slipped slightly a few times then when I came to a stop engine died would not restart after 10 minutes or so restarted ran fine, occasionally felt the slip, it seems more like the engine is cutting out and not the transmission. I was looking at it yesterday and it died after it had warmed up. Finally I was at home so I could start looking at it. When you try to restart, the engine fires for a second and it smells rich from the exhaust it seems like it is getting fuel.
Cleaned the maf with cleaner. no change
I thought maybe temp sensor was the problem or the maf.
Engine temp sensor shows about 200 ohms when engine is hot.
Mass air sensor reading with engine running. =
pin 1 to pin 2 = 35 mv
pin 1 to 3 = 13.0 volts
pin 1 to 4 = 1.029 volts
These are readings from the back of the connector. plugged into maf.

When engine dies and no restart. unplug maf engine starts and idles fine I did not drive it put it did accelerate.
I am not sure if the maf is bad or if I have a bad connection.
I do have a evap code for small leak is it possible that the evap. purge valve could be opening and causing a vacuum or air leak that the maf is seeing and trying to correct causing the engine to die? I have not been able to find the leak yet but I am not convinced it could cause my problem.

 

The symptoms you describe are more like a cam sensor going out. That is easy to diagnose when it won't start, but of course impossible to diagnose when it's running.
You ought to get an OBDII scan tool in my opinion. You can monitor the measured air flow when it's running.