My 86 740 GLE does exactly the same thing. I would be interested to know what your idle speed is with the car in drive, foot on the brake, A/C off. Mine is usually around 700rpm. I usually use the A/C all year round because it's less likely to stall slowing down at a stop sign becuase it idles higher. But, even with the A/C on, it sometimes will start to slow down like it's loosing power almost to the point of stalling and suddenly pick up again. I won't let my wife drive it and I've had this problem for two years. I replaced all the normal tune up parts, flame trap, etc, and even the engine computer with no change. Rubber hoses look fine and wiring harness was replaced with the good stuff. Maybe I'll change the crank sensor too and see what happens.

Paul

86 745 GLE IPD/MM11's/BOGE/Intrax
94 945 Bilstein HDs