Oil smoke coming from exhaust. Where do I Start looking for problems. on 2001 BMW X5

Drving down road. puff of black smoke came out exhaust. Got home and strong smell of oil from exhaust. Engine now hard to start. What could it be and where should I start looking. Thanks

Asked by for the 2001 BMW X5
1 answer
black smoke is normally fuel related.i would save time and $ and see your mech