One problem related to steering wheel vibrate has been reported for the 2003 BMW Z4. The most recently reported issues are listed below.
The contact owns a 2003 BMW Z4. When the weather was warm the steering wheel was shaking excessively. It became difficult to keep the vehicle in the middle of the road especially while driving over 30 mph or more. The vehicle was taken to the dealer on several occasions regarding the failure. The dealer stated that nothing was wrong with the vehicle. A report was filed with the manufacturer who stated that they were not aware of the failure. The failure mileage was 10,000 and the current mileage was 18,000. Updated 10/20/10 updated 10/22/10.