Sounds more like a bad Idle Air Control valve or Coolant Temp Sensor. One thing a vacuum leak will do is cause your car to idle faster and perhaps set a check engine light as you have unmetered air in the intake.
Replaced ICV, CTS, TPS, injectors, vacuum lines, AFM, Intake plenum elbow, upper/lower gaskets, exhaust manifold gaskets (still sounds like an exhaust leak though), ECU, Plugs, wires, checked coils. Car runs better than it did before all the work... but it still does the hesitation/stalling on initial startup. Even my local shop is stumped (taken Bmw's there for 10+ years) and they've never been unable to diagnose a problem.
LOL I'm flabbergasted. Rebuilt motor only has 34,000 miles on it. Previous owner of said motor said it didn't do that in the car it was in. I drove said car before it was removed. It was originally installed in that car by BMW dealership in 2003. Soooo... solution to me has to be something external to the motor itself, like the booster...? Possibly wiring harness, but I don't know why it would ALWAYS run perfect after about 2 minutes.