Volvo 940 Dies, All Dash Lights On

We bought a 1994 Volvo 940 Turbo Wagon when it was new. My wife has driven it for 16 years without a problem. Now, without warning, the engine stops, all dashboard lights come on, and she has to pull off the road. The car has, up to this point, re-started without problem from park or neutral. This has happened about 6 times over the past 4 months. She wants to sell the car because she can’t stand the uncertainty of when or where it will die again and whether it will start or not. Our mechanic has no idea what’s wrong. He said to tow it in next time it happens and maybe he can figure out the problem. It has always started up right away after dying so I don’t want to have my wife call a wrecker just to find out the mechanic still doesn’t know what the problem is.

Have the mechanic clean, or replace the MAF (mass air flow sensor). It should not be too expensive. I had similar stalls on a '98 Volvo and eventually the MAF failed completely and the car won’t restart.