general problems of the 2004 BMW Z4

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.

I own a suspected Z4 with a NHTSA reported "sticky steering" issue I can tell you a little more about it. The problem has nothing to do with the boost. When the car gets hot (summer hot) the steering gets notchy in that when you put the car in a slight turn, like changing lanes or going around a slight corner, the steering literally sticks in that position causing the driver to apply opposite pressure to "break" the wheel loose from the turn followed by another stick wherever the wheel is brought back to. Problem is that it causes massive over steering issues at high speed unless you are looking for it. Extremely dangerous at highway speeds! BMW knew about it and released multiple pumas (their equivalent of a TSB) and even redesigned the suspect column, but refused to replace the older ones out of warranty. These are $3000 before labor and BMW has flat out told me that they won¿t cover a single dollar of it. I guess we will see NHTSA forces their hand! I am scared to death to drive the vehicle I had to jerk to out of another lane several times and you must work extremely hard to keep it straight. Please do something before someone gets hurt.