I have a 2004 Z4 3.0i. Something weird happens with my audio system. When I start the car it functions ok but after a few seconds or minutes (it depends) it doesn't sound. I have to restart the car to make it work again but it is amazing, depending on how I insert the key it will operate or not (I have to try several times). Did it ever happen to you or do you have idea of what might be the problem? Thanks.

Mine does this....sorta....after I synched my Blue Tooth phone with the car. However, the sound always comes back after 2 or 3 minutes. When the phone is not synched, the stereo operates with no issues.