I posted this message a year ago (April 2009) for some reason I can no longer reply to it and bump it up:

http://www.brickboard.com/RWD/index.htm?id=1345903&show_all=2

At the time I was cruising down a highway when all of a suddenly the car started sputtering, much like missing a cylinder or two, until there was no response to depressing the gas pedal, and within one minute of this it stalled. This happened at around 2 pm, warm weather, after the car had been running pretty much non-stop for 6 hours. Waited 15 minutes and the car started it up, then stalled again. Was able to limp it to Savannah but it stopped every 10 miles or so. The dealership tested it the next day and couldn't reproduce the problem. I drove the car home without problem (300 miles). Switched the fuel pump relay as a precaution, and car ran fine for a year.

So here is the update: This month, exactly 1 year and 10,000 miles later, I was again on a trip when the same thing happened at 5 pm, warm weather, after the car had been running for 8 hours with no problem. It would start again but I didn't want to drive it home with 70 miles of low shoulder roads to go so I had it towed (AAA).

It started right up the next day and I drove it some around town but not much. Switched out the fuel pump relay as I had a spare. Will check for spark next time it happens but right now I am at a loss. OBD reads 1-1-1

Fuel pumps (both) were replaced about 5 years ago. Flame trap was cleaned a year ago. Not sure when the fuel filter was done - not on my watch so it's been 4 years. Will have that addressed next time.

The windshield wiper motor, per Volvo dealer, is leaking so we think that water has been getting on/into the relay and possibly the ECU. Area has been resealed and I am leaving things open so I can assess the moisture issue next time it rains. It had not been raining when the above incident(s) happened.

I know this could be many things...