I did some more investigation today because the car is now stalling at idle unless I put the car in neutral. It has also become hard to restart hot. I looked at the emissions diagram under the hood and now know that the component that had the broken vacuum hose is the fuel pressure regulator. I put an all new hose from the regulator to the manifold, but it still runs rough and stalls. Since I haven't gotten any feedback on this from the board, I'm going to take the car into my independent MB shop tomorrow and have them check the codes. My hunch is that it needs a new fuel pressure regulator, but I want to be sure.