Inspect and test all the following listed below: Oxygen sensor.
Fuel injectors dirty/sticking.
Mass airflow sensor/Airflow meter.
Throttle position sensor.
Manifold absolute pressure sensor.
Fuel pressure regulator leaking or defective fuel pump.
False air leakage.
Foul/defective spark plugs.
Open spark plug wires.
Ignition coil/Coil packs defective.
Incorrect ignition timing.
Cap and rotor.
Note: If it doesn't apply disregard.
June, 9, 2010 AT 4:24 PM
The coils are possibly in need of replacement, there is a recall from BMW on some of them.