2004 BMW Z4 Electronic Stability Control Esc Problems

THIS IS A REOCCURRING PROBLEM WHICH I HAVE ATTEMPTED TO ADDRESS THROUGH BOTH LOCAL MECHANICS AND BMW WITH NO RESULTS. ESSENTIALLY, WHILE MOVING AT SLOW SPEEDS OR STOP AND GO TRAFFIC, THE ELECTRICAL SYSTEM "SHUDDERS", ALL INSTRUMENT LIGHTS ILLUMINATE, THE TRANSMISSION SHIFTS TO NEUTRAL, AND THE ENGINE SHUTS DOWN THEN RESTARTS. THE FAILURE OCCURS ON AN IRREGULAR BASIS, AFFECTING PRIMARILY THE EPS LIGHT, BUT MAY ALSO AFFECT ALL LIGHTS IN THE INSTRUMENT CLUSTER. LIKEWISE, IT MAY OR MAY NOT MOVE MY TRANSMISSION TO NEUTRAL AND IF THAT HAPPENS, MAY OR MAY NOT ALLOW MY TO PLACE IT BACK IN DRIVE WITHOUT SHUTTING THE VEHICLE DOWN FOR SEVERAL MINUTES. TO DATE, BOTH THE ALTERNATOR AND THE IGNITION SWITCH HAVE BEEN REPLACED, NO RESULTS. A BRIEF SEARCH OF POPULAR BMW FORUMS FINDS SIMILAR DESCRIPTIONS FROM OTHER OWNERS.

LOSS OF ELECTRICAL ASSISTED STEERING/STEERING WHEEL VERY SLUGGISH. *TR

I HAVE A 2004 Z4 THAT I PURCHASED LAST AUGUST USED. I RARELY DROVE THE CAR AND KEPT IT MAINLY FOR LEISURE UNTIL THIS PAST JULY. THIS JULY, ON THE DRIVE FROM WARNER ROBINS, GA TO HILTON HEAD, SC, I NOTICED THE STEERING WOULD STICK AND I HAD TO USE FORCE TO GET IT BACK ALIGNED WITH THE ROAD. SINCE THAT TIME EACH DAY WHEN I LEAVE WORK AFTER THE CAR HAS BEEN PARKED ALL DAY IN THE HEAT IT DOES THE SAME THING. ITS ALMOST AS IF THE CAR IS TRACKING. NORMALLY MY SPEED DOES NOT EXCEED 40 MPH. I HAVE HAD THE TIRES CHECKED, THEY ARE NEW RUN FLAT TIRES, NO PROBLEM, I HAVE HAD IT ALIGNED AND I AM STILL HAVING PROBLEMS WITH STEERING WHEN TEMPERATURES EXCEED 85 DEGREES. IT DOES NOT DO THIS IN THE MORNING WHEN THE TEMPERATURE IS BELOW 80. IT IS SOMETIMES SO...