1995 BMW 318 Car stalling

For about a year now I have had problems with my car idling rough, stalling and dying when coming to a stop. When it sits for a while it may or may not restart and run fine for a couple of days. I have had the following work done so far: O2 sensor replaced, fuel pump, spark plugs, front brakes, and most recently the air intake valve. The car ran fine for about 2 months then the symptoms returned, so I took it back to the bmw shop and they could find nothing wrong as the car ran fine for the 3 days they had it. So I brought it home and discovered that when the car starts and dies if I tap the brakes 2-3 times it starts up and runs fine for 2-3 days. I have done this twice with the same results except for an occasional rough idle and being able to hear a slight engine pull when I operate the power windows. So I called the BMW mechanic to let him know about this and he was baffled and said he would do some research and get back to me. What are your thoughts?