Stalled 1995 Saab 900 SE

Last night as I was heading home, I happen to look in the rear view mirror and noticed what appeared to be smoked coming from the rear of my car

(could not tell if it was blue or white). I was about two minutes from home in a 10 minute drive so I contined home. After I got home, i checked the exhaust and it had no smoke smell. I remembered that the smoke trail seem to be concentrated on the passanger side, so I bended down and sniffed all four tires. The tires on the passanger side smell smokey the tire on the drive side had no smoke smell. It was my intention to drive it to work today and call the mechanic. Guess what? We(the car and I) never left the driveway. It made this chattleing chug chug sound and stalled. Now it does turn over, but does not start. The last time I got an oil change (which I’m very good at) the Saab mechanic inform me that I had a tiny hold of sorts( I forgot where under the hood), that was going to cause the car to get louder and louder. He did not advised me to do anything about it then, he said eventually the noise would get so loud that I would want to take care of it though. I did begin to hear this noise coming from under the hood. I must also add that about 1 year ago I was hearing a very faint noise that sounded like wind was blowing through a very tiny hold some where on the front passager side (around where the tire would be), Took it in to the mechanic then, but of course the sound would not reproduce for him and we took it on the road together and drove and drove and drove. I assumed when he told me about this hole a year later that it was indeed that noise and that the problem had just progess to the point where it was now noticably by him. My mind is now thinking, was this the same problem or two different problems and when I heard this noise, getting progressive louder, oh for about 3 weeks now. I was waiting until my next oil change to see what the mechanic had to say. i am now thinking maybe the noise(which normally I would have paid attention to and bring it into the shop) was not the same noise the mechanic had warned me about. So the car has been towed to the shop, but in the meantime I was wondering what anyone out there might have an opinion about what could have happened.