Volvo 740 died, suspect ECU

Help! My 1990 Volvo 740 died again. 6 months ago it came to a complete stop in traffic. The starter was turning the engine but it wouldn't fire. After checking everything including the fuel pump and relays I discovered that a remanufactured $500 ECU (BOSCH # 0 280 000 556) fixed it. Last night the problem returned. I'm not plunking down another $500 for 6 months of driving. Obviously there must be other electric problems causing my ECU to die. Any suggestions?

Thanks.

Look here (http://www.brickboard.com/FAQ/700-900/) for troubleshooting info.

Thanks, found out I had a bad relay. Was shutting off the fuel rail. Cost about $50

Look here (http://www.brickboard.com/FAQ/700-900/) for troubleshooting info.