Here is a story to read original copy pasted

its what professional workshops are struggeling with these days. its from a professional only forum but i recon this would be good for anyone to read and it wont just be vw where this can cause this exact problem
fuel is metered so precise these days that there is no room for errors zerro tollerance for things not 100% the way the engine managmanet needs things to be now.

2004 Volkswagen Beetle GLS 2.0L Stall
This thing is driving me nuts! It will run fine in the bay for as long as you want, but if you take it out for a test drive it will stall (no symptoms). It doesn't sputter or give any warning, and it doesn't matter if you are accelerating, cruising or on a decal, or coming to a stop. There are no codes, and it doesn't drop fuel pressure when it stalls. It has restarted every time it has stalled, sometimes with an extended crank, but always in traffic, so no testing can be done.

When it stalls it gives no warning, no telltale sputter, or buck or anything, just lack of throttle response and loss of rpm. The warning lights do not come on until you come to a stop, or put it in neutral.

Have any of you VW techs run into anything like this? I don't know where to go from here.

FIX posted on Apr 30, 2015 7:49:54 AM

Well this was a good lesson in going back to basics and getting the whole story from the customer. I found out that this vehicle had been to another "repair shop", which I think was under a shade tree in someone's backyard. Seems said shop installed a fuel pump to correct this stalling problem, twice. The first pump ran for about two blocks before it quit, and the second was the one that was in the vehicle when I got it, both pumps were aftermarket. This vehicle uses two different diameter fuel pump assemblies, one is 110 mm and the other is 120 mm. The other "shop" installed the smaller of the fuel pumps in this car, the problem with that is that this car takes the larger pump. Imagine my surprise when I get a replacement pump (being the smaller of the two since that's what I took out) and it doesn't fit the hole in the top of the tank. I ordered the larger pump (original equipment) and got it installed and my fuel pressure and volume increased. Vehicle has not stalled since installation.

Thanks for all of the help!

Just lucky a 'B' Train or a bus didn't run over it ?

But the fuel pressure didn't drop if there was a lack of flow, fuel pressure would drop. would of thought symptoms would of showed under heavy acceleration