Volvo Repair: 91 940 Turbo stalling, fuel pump relay, throtle body

Question
I have a 91 940 Turbo SD with 135K it recently started to stall while driving. I've installed a new radio suppression relay, a new fuel pump relay all factor parts.  Problem still continues.  I took car to certified mech who told me these relays were bad so I replaced them and I still have the same problem.  What should I consider next idle valve? throttle switch or some one told me it could be a hall effect switch on the distributor.  I see a lot of folks are starting to have the same problems with this model but I have not seen one positve response to recommended corrective action.  CAn you help a active duty military guy out?

Answer
James, The only positive response would be if I personally checked the car out and diagnosed it.  I would check the speed sensor on the bell housing first.  If its chaffed, then replace it.  There is no hall effect on this one.    If you took the distributor apart, there is nothing in there, unless you got a model the has a black plug at the back of the dist but that was earlier years. If you told me that the car was stalling while coming to a stop then a throtle body service is in order.  I would still do it for a precaution. There are tests to be performed but on this service, but I can only suggest things since Im not personally looking at the car.  Thanks for being a military guy.  I was once one too.  Roger