I doubt it's the fuel pump, try rapping on the MAF with your knuckles. Have a look at the spark plugs. If you want to replace parts then cam sensor would not be a bad idea. The brakes should work like normal at least for the first application when the cars stalls, so something probably going on there. Smoke test doesn't rule out a vacuum leak.

OK I see you replaced the cam sensors, but with OE parts ?? why was the crank sensor replaced ? was that replaced with OE ?? If the problem started after the crank sensor replacement that is highly suspect. Are you reading all the codes with your scanner ??

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1988 325is (purchased new) sold
2004 X5 3.0 2005 X3 2.5
2008 X5 3.0 (new to me)