Volvo Repair: 1985 volvo DL245 random stall, fuel pump relay, volvo dealership

Question
Greetings-

I have a 1985 Volvo 245 DL manual transmission with 254k miles.  Yesterday when driving down the highway the engine suddenly and without warning (no sputtering, slow loss of power, etc) died.  I left it in gear, which caused the engine to still 'run', but no throttle response.  It slowed from about 60 to about 40 mph, then miraculously and suddenly started back up with full power as though nothing had happened.  Unfortunately it did this about 10-15 more times on my 20 mile trip home.  Sometimes it would restart in a couple of seconds, other times it would slow down to 20 mph before restarting itself from engine compression.  

I consulted my regular mechanic, who admitted having very limited knowledge of Volvos.  He in turn called another mechanic at the local Volvo dealership who suggested the fuel pump relay. I managed to get home and ordered a new relay from the parts store.

I installed the new relay today hoping that would address the issue.  I drove around town fine, then it died twice on me.  Of course this time I was not at highway speeds, so I had to sit and crank the engine (once in the middle of an intersection) until it finally started.  Then again no sputtering or other indication anything was about to happen, and then it ran fine after restarting.  When cranking the engine there was no sputtering, but it was cranking solidly.  as though all that was missing was fuel.

I am certain if I take it to a mechanic he will not be able to reproduce the problem in a five minute test drive.  I would also like to avoid a shotgun approach to repair by simply replacing various things trying to guess at what might be wrong.

It seems to me that if the fuel pump was going bad it would not be so off and on.  I also suspect if it was a coil issue it would take longer than a few seconds or a minute or two to cool down enough to get it going again.  But then again, I'm not the mechanic :)

Any help would be appreciated.  We got this car for free from a family member and I would rather not spend more on repairing it than it is worth.

Answer
Joel, all those theories are good.  I have seen this happen before on the older 240's and it turns out to be the connector on the ignition control unit.  Im not ruling out the fuel pump idea or the coil but if it is the control unit itself, its a pretty expensive part.  Have it checked out by a Volvo Specialist.  Roger