Hesitation 528it with M52TU Engine

[cregg62]

My 99 528it wagon (with 140K miles) has hesitated about fours times while traveling on the freeway in the past three months. It happens when I decelerate (take foot off the accelerator pedal) and then accelerate; there is no response from the engine for 1/2 to 1 second. The EML did NOT come on or set.

Yesterday I drove the car and about block down the street there was no response when I pressed the accelerator pedal. I had the pedal to the floor and the engine would only idle. The EML light did come on. I drove the car back to the house about three blocks total, about 1/2 block before reaching the house the car would accelerate when I press down on the accelerator pedal. The EML light went out also. (I parked the car and drove another car to the funeral) Upon my return late in the afternoon I drove the car with out any problems. The following day I got up early and test drove the car try recreating the conditions, the car worked with out any problems.

I tried to retrieve EML code with inexpensive code reader but I think erased the code.

Other problems that might be related:
Some times the car idle when cold will drop off then pick up all with in a 1/2 second or less and will continue until the engine is at operating temp. Some time the engine will die but can be restarted. There is a whistling noise along with engine rpm dropping.

Any assistance in pointing me to cause of this problem is greatly appreciated. Photos of the components and location would also be a great help