Yes, "I met an oncoming car" is a correct sentence in English. In this context, "oncoming" is used to describe the direction of the car - it is approaching from the opposite direction.
In English, "meet" can be used to describe an encounter or crossing of paths with someone or something. When used in the context of vehicles, it often refers to encountering another vehicle on the road.
So, "I met a car" or "I had/got a meeting with a car" would also be understandable in English, but "I met an oncoming car" would be a more specific and precise way of describing the encounter, particularly if the context implies that the encounter occurred on a road or in a similar situation where vehicles are expected to be moving in opposite directions.