1991 Mercedes 300e Stalling

91 300E 125K miles, runs beautifully on the highway. Recently tuned, all fluids and wires replaced or checked. Car repeatedly stalls in a peculiar fashion - after driving a while, often at slower speeds, after the car comes to a stop it will stall as I try to start moving again, just when the gas pedal is pressed. It feels as if the gas line may be not allowing fuel to pass up the line. Often the engine will again start anew, but too often it will not and thus the vehicle is unreliable to drive. Does this sound familiar to anyone? (3 mechanics thus far have not figured it out)