Just stalls and no one knows why....

I have a 200 745i and with just shy of 100k miles. Now the car just stalls and sometimes won't start of hours and sometimes pretty quick.

I have had this taken into 3 shops and 2 of them are BMW certified centers. The answer is that no one knows why. I mostly get that this car has a lot of issues and to pinpoint is very difficult, especially with these cars. They service centers are having problems replicating the issue, however it did stall one time while they had it in their possesion and hooked up to some kind of "computer" and apparently the codes don't give them any resolution.

So i am trying to figure out if i should take it to an actual dealer for repairs? My concern is that everyone seems to say that you will eventually fix the problem, but only have you just keep spending $$ on each item to repair. Sooner or later you will hit the issue, but you will dump thousands of $$ into the car before you get there. I have replaced the sensor for the air (air meter sensor), still not helping.

So what would you all recommend? Anyone else having this issue?

Again, the car sometimes stalls (usually when at a light or stopped in traffic) when i am stopped for a few minutes. Not all the time, about 1/ week now. And after it stalls i can wait a few minutes and it will start or it could be hours. In the latter case i have the car towed and the BMW certified location tries hooking up different batteries and such and nothing seems to work.

Help please-

Just stalls and no one knows why....