Air Bag On-off Switch problems of the 2007 BMW Z4

While in motion the vehicle accelerates for 2 to 3 seconds periodically on highway and in city. While in motion at low speed and when stationary after driving only a few miles the vehicle engine shuts down. While in motion at high speed the vehicle engine stutters badly but does not turn off. The ignition switch has to be tuned off and then on again, and then the engine turns over and I'm able to continue to drive it. Both valve cover gaskets leak oil onto the engine. The worst was front of the engine which has been replaced. There is an electrical issue: seatbelts don't retract automatically and are not working properly, get caught in the door. Both e-keys have stopped working and not able to be reprogrammed for en. The horn does not work at all. The airbag warning light remains on at all times. The cig lighter and seat warmers are working fine. The thermostat warning comes on but in gauge is not showing any sign of trouble. Both the heat and the ac work fine while in motion and stationary.