Volvo: 850 Stalls, fuel pressure gauge, cam shaft position sensor

Question
1993 850 normally aspirated 180K miles B5254S engine    Engine quits (stalls). My engine will stall two or three times a week. It happens when the engine is warm and at speed. There is no hesitation or rough running prior to or during the stall.  It just stops.  It almost always starts again without hesitation following the stall (once it took several start attempts to run).    I have checked for fault codes in the fuel system (no fault detected) and the ignition system (3-1-4, cam shaft position sensor signal absent). I check for codes each day.  Normally both ignition and fuel are 111 (no faults).  On some occasions after a stall the 314 shows up other times after a stall I still get the 111.  I changed the fuel filter.    Any ideas on what and how to check.    Thanks,  Skip  

Answer
Skip,
With the cam position sensor code occuring at times, I would go ahead and replce it and see how that works out. If you do change it make sure the connection are clean and tight. Try a fuel pressure gauge that you can read while driving, see if you loose pressure before the stalling. If so maybe fuel pump relay or pump itself.