i noticed some vibration during idle(whole car vibrating) . the car can be in neutral or stopped at the light and will start vibrating pretty bad. not a violent vibration but mild, it just makes me worried. after I noticed the vibration I changed oil, oil filter, spark plugs, fuel filter, k&n filter, cabin filter, o2 sensors front and back. I've been putting in a fuel injector cleaner during every oil change and nothing helps. does anyone have any other suggestions or ideas what it could be? This car is in tip top shape other than the vibration. I have a 318i 98. sounds like the engine could be running rough, but what can I do to repair the problem? please help