1998 Ford Contour Rattling Noise and Stalling

It's been a week since I bought my 1998 Ford Contour and as I was making across the border this morning, I noticed a rattling sound coming from underneath the hood. Not sure specifically sure where it was coming from but I'm sure it's under the hood. When I got a feeling that the car was going to stall on me, I pulled out of line and as put on the brakes to make a stop at the stop sign, the car stalled. I put the car on park and turned the ignition on again fired right up. When I went to accelerate, it stalled again. Fired it up again and drove to the coming traffice light and it stalled again hearing the same rattling noise. Started it back up again and when I came to the next traffic light, it stalled again. This time I saw white smoke coming from the tailpipe when I fired it up once again. What could be happening to the car I thought was in good conditions?