My son has a '95 850 at school. One day he tried to start it, got nothing - totally dead. No click, nothing. Figuring the battery was dead he got it jumped and bought a new one.

Apparently that wasn't the problem because when he drives the car now it stalls with no warning. So far he has not been stranded - it either starts again right away or won't start for a few tries but then starts. He is pretty sure at least once when he tried to restart he got nothing (totally dead, like the first time before replacing the battery) although usually even if it won't start it at least cranks.

In the archives are several threads about failed fuel pump relays causing intermittent stalling. That sounds about right and I'm inclined to risk $30 to find out but it doesn't explain when the engine won't even crank. I found one post that mentioned a dead "main system relay".

This is hard to diagnose, and I don't even have access to the car (500 miles away). Suggestions on how to troubleshoot?

Symptoms in a nutshell:
- car stalls with no warning, no pattern
- car otherwise drives fine
- sometimes it will restart right away
- sometimes it takes a few tries to get it to start
- on some restarts the engine won't even crank, get no lights, nothing

Does this point to a bad main relay, fuel pump relay, or something else?

Thanks for the help,

Terry