I have a 2001 E38 740IL that when reaching cruising speeds 45+ the car has a surge or stall problem(cant distinguish stall or surge) but disappears if I accelerate. My mechanic cannot see any fault codes so he says to let it run till it breaks. Anyone know whats going on? This car has had this problem since I bought it 20K miles ago. Never been stranded and the ole girl always starts and good acceleration.