Volvo: Intermittent stalling while moving and then hard restart, fuel pump relay, volvo 740

Question
Ray

I have a 1992 Volvo 740 wagon with 240k on it. I had stalling and ideling problems at low RPM which have been fixed (at a cost of $500) but another hidden stalling problem that was masted remains. This occurs only while moving at any speed. The car just stalls (and the lighs go out) and often can not be easily restarted until it sits for 60 to 120 seconds. Sometimes, I get lucky and it restarts in neutral before the lights go out. This happens very intermittently. It may have 3 times in a row and then not for a week. However, it is becoming more frequent.

Volvo tells me it is either the Power Satge Switch ($200); the Fuel Pump Relay ($100) or the Fuel Pump ($400+). Trying to simulate it at a mechanic is probably a waste of time.

Your thoughts would be greatly appreciated

Answer
Frank,
There in fact must be a reason for the stalling, but until it will do it for someone that can do some testing what to look for is a tough call. Lights go out? Are those the instrument warning lights? That would sound like a power or grounding fault. The starter still works when that happens? I would say then that just that cluster area is affected. You need to know if during that time is power also lost to the fuel pumps? Look at the alt connections make sure that the ground wire is good and tight. The items you were told could be the cause will keep the engine from running and cause a stall, but I can't see a relationship with the dash lights going out. If you jiggle the ignition switch will they come back on?