1992 940 turbo w/280K. Owned since 140K. Has always occassionally died, but was infrequent and would usually restart within a few attempts, and it never stranded me before. But lately it dies more often, and it sometimes won't restart until after sitting for a while, sometimes a few hours. Usually happens when slowing or accelerating, typically at lower speeds; has never happened at higher speeds. Happens after engine is hot and car has been off for a while and then restarted; typically happens within a few minutes of driving afterwards.

Here's what all I've done so far. Replaced main fuel pump and relay (in-tank pump was replaced a few years ago). Replaced crank position sensor, coil, plugs, ignition wires (distributor cap and rotor were replaced within the last 10-15K), bosch ignition module, and suppression relay. Reworked the 4-pin suppression relay plug to ensure a good connection. Tightened grounds. Problem persisted after each change. Most recent change was replacing the ECU with one I bought on ebay. After that change, during the 4th or 5th 10-minute test drive of the day, it died again. It seemed to die more abruptly after the ECU change than before (before it would typically stumble some and then die, whereas this time it died without warning), and it restarted a little easier (restarted after sitting just a few minutes rather than taking much longer as it sometimes had been taking before), but it still died about the same way and under similar circumstances.