1996 e38 engine bogs down occassionaly

I haven't seen anything quite like it on the other treads. My tail of woe is this. Car always starts fine and idels fine. When I start driving after about 1/2 mile sometimes it just starts running like crud, bogging down, no power at all and the engine starts making additional noises. When I come to a stop it is just barely idelling and most times will stall. Now the strange thing is, if I turn the car off and wait about 30 seconds. When I start the car again, it will run fine. Sometimes it will run fine for the rest of the day with no problems. Sometimes when the car is restarted, it will bog down again in a couple of miles. There seems to be no real pattern on when this will happen, and it's happened when it's cold or hot outside. The only consistent thing I can identify is that it is more likely to bog down the 1st time I drive the car that day. Any insights would be much appreciated.

When you have such a problem: stop the car, let engine run in idle, remove the cap from the fuel tank. If you hear a loud hissing sound as if air goes into the fuel tank, then you have a problem with the airation system as there is vacuum in the tank.
Known problem, even some fuel tanks were shrunk and cracked by the vacuum.

had the same exact problem, went to a diagnostic center, spent $150, and found out that the Mas Air Flow Sensor is bad. dealer charges $499.00 . found it on e-bay for half that.. car improved 90%. now need to change the O2 sensors....

Thanks to the previous replies as I brought them with me and gave to the mechanics to review. I took the car to local mechanic who does my routine maintanence and they couldn't figure it out. They cleaned the "hot wire" on the Mas air sensor as they said it had some crud on it. They replaced a couple of rusted 'check valves" with no success. Then they said it probably needs to go to the dealer for some advanced diagnostic. Took it to local BMW dealer in Hartford, New Country BMW. They cleared all the codes and it keep showing the left throttle body was the problem. They replaced the left throttle body and now it's running fine The cost was painful, $1400 for the dealer diagnostic/new trottle body/installation and tax. Plus the $350 for my local mechanic to do basically nothing, so my wife is not too thrilled with me right now. But what the hell I need the car to run right. Took a 3 hour ride up to Northern Massachussetts for a wedding and did 85-90mph all the way with no problems. The only issue now is keeping my foot off the pedal as I could easily been doing 100mph+ and not even pushing the engine.

The throttle bodies you can actually clean.
Dealer told me the same for my 750 which has 2 of them and each one costs here in Japan 2000 $.
Cleaned them and they work since years fine. Did the same on my other 750.

Procedure is on my website below.
Keep the old throttling valves and clean them, I hope they did not keep them.