NHTSA Complaint #10561948 — 2007 BMW X3 SAV

SEVERE ACCELERATION AND DECELERATION ISSUES WITH TRANSMISSION ON 2007 BMW E83 X3. ONCE THE ENGINE HAS REACHED NORMAL OPERATING TEMPERATURE, TRANSMISSION ISSUES ARE MORE NOTICEABLE. MY VEHICLE DOES NOT RESPOND IMMEDIATELY TO THROTTLE INPUT WHEN STARTING FROM A DEAD STOP. SEVERAL HESITATIVE JERKS ARE FELT AND THEN THE VEHICLE ACCELERATES VERY SLOWLY. OFTEN TIMES DURING THIS SEQUENCE, THE EXHAUST EMITS A HUGE PLUME OF SMOKE, BLINDING DRIVERS BEHIND THE VEHICLE. UPON DECELERATION, MY VEHICLE MAY DOWNSHIFT HARSHLY, GENERATING A FORWARD SURGE OF ACCELERATION BECAUSE THE TRANSMISSION FAILS TO MATCH ENGINE REVS WITH THE LOWER GEAR; I HAVE ONLY EXPERIENCED THIS PARTICULAR CHARACTERISTIC AT LOW SPEEDS (<20 MPH). ALSO WHILE DECELERATING, MY VEHICLE MAY LOSE POWER, WHICH RESULTS IN A LOSS OF POWER STEERING, MAKING THE VEHICLE VERY DIFFICULT TO TURN. I HAVE NOT BEEN ABLE TO DETERMINE A DECELERATION RATE THAT "TRIGGERS" THIS BEHAVIOR. I AM A TEST ENGINEER AND A PERFORMANCE DRIVING INSTRUCTOR WITH BMW CCA. I HAVE REGULARLY DRIVEN BMWS OVER THE PAST DECADE AND HAVE NEVER EXPERIENCED THIS ISSUE WITH ANY OTHER MODELS THAT I HAVE DRIVEN (E46, E39, E63). I ALSO HAVE LIMITED RACING EXPERIENCE IN E30 BMWS. I.E. I KNOW HOW AN ENGINE/TRANSMISSION IS SUPPOSE TO ACCELERATE AND DECELERATE UNDER A WIDE VARIETY OF CONDITIONS. THESE ACCELERATION/DECELERATION ISSUES ARE VERY CONCERNING TO ME. *TR