I bought my 86' 240 several years ago and had some intermittent drivability issues. Under load it occasionally would fail sputter hard, but not quite stall--or perhaps I didn't wait long enough before easing into her. Sometimes it wouldn't go above fifty--especially under heavy acceleration. Being young and foolish, I replaced both fuel pumps, the wiring harness, and in the end, it was the Air Mass Meter. That said however, I am now having nearly an identical problem.

(Note: unlike last time, I am now on the East Coast and the weather is near-zero degrees.) I just had both fuel pumps replaced--again, this time they definitely failed--and so I'm wondering if I'm missing something? When the car acts up--usually only if it's only been running for the first time in the day--if I pull over and restart the car, it then works fine. (Recent replacement of fuel pumps may be unrelated--as I installed them the first time and likely did a poor job.)

For the record, my car just had a major tune-up but may need a new timing belt.

Thanks in advance for help!

If your car works fine when warmed up, but not when cold. Probably air/fuel mix too lean for the cold weather. Resulting in hesitation, backfire, poor acceleration.

Wow, it seems that lots of people are having this problem.
Myself included,

I have been working on this problem for some time now, and is really pissed off.

I got a new pump, new fuel pressure regulator, new wires, new plugs, new cap and rotor, new fuel pump relay, yet problem continues (yes, wires and fuses are great)

my research in the archives leads me to think the problem is definitely fuel related and could be

transfer pump and sock
fuel filter
fuel pressure check valve
fuel hose between transfer pump and main pump
RPM sensor (but this is a far stretch)

I ordered some more parts from FCPGroton and will be replacing more parts this weekend,

If somebody out there can offer a solution, PLEASE email me and let me know,
xyliang@hotmail.com

Boy, that sure sounds like the fuel pump relay might have cost you a ton of money in unecessary fuel pump replacement. Dealers use that little part to sell pumps and I have to think they are not truly naive enough to be unaware of the common relay problem.