1997 Cadillac Deville Check engine, hesitation, stalling out

The check engine light is staying on. Had it checked and was told that the problem is a vacuum line. Don't know which vacuum line yet. At times the car hesitates like it's not getting fuel then all of a sudden jumps forward. The other problem it has is while doing any where between 15 and 35 miles an hour around a corner or curve the oil light will come on and the engine will die. I don't know if these problems are all linked together or are seperate problems. I'm just trying to get an idea of what might be wrong before I take it to a mechanic to be repaired.