My lovely green beast isn't dependable anymore. Sometimes dies in the middle of the road, sometimes won't start. I started replacing all those parts that I probably should have replaced thousands of miles ago: fuel filter, both fuel pumps, fuel pressure regulator, those two relays by the ECU, fuse by the coil...

Had replaced the wiring harness and it ran for awhile, and I do wonder if it might have something to do with that. I guess I should go wiggle everything and push contacts firmly to make sure something didn't come unplugged. Cleaned the throttle body (though I didn't take it apart, just sprayed and wiped and sprayed and wiped and it's a lot better than it was). Flame trap and all those things under there that y'all suggested taking care of on this board (many thanks!).

Couple times, I thought I'd fixed it, but then it dies again. AMM-unplugging doesn't change anything. It's running rougher and rougher, it seems, when it does run.

Took it to a "Volvo specialist" who said it had bad spark plug wires, and that that would cause an intermittent problem, and they wouldn't check anything past that for their $70 diagnostic fee (they said they checked and the fuel pumps were fine). Well, I'm not really a real mechanic, but I find that hard to believe. The SP wires don't look bad, but this multimeter doesn't have any stops between 2K and 20K ohms (I read that it should be 10 or 15K ohms resistance) so I can't check it yet anyway.

MY mother had a 760 or one of those others that had a very similar problem, and I thought I would remember what the mechanic finally figured out it was, but no such luck.

I don't know where to go from here.