OK, my car was sitting for a few hours after a day of driving...when I started it, I noticed a strange vibration, and that my engine didn't quite sound right. I pulled out of my driveway and the car was VERY sluggish, so by the time I got to the end of my street, I turned back, knowing something was wrong...when I pulled the car into the garage, I left it running, and gave the engine a couple of revs...as I let go of the gas, the car gave a slight shudder, then you could hear the engine ALMOST give out, but it would keep going (even the interior and dome lights would dim, so you could tell the alternator was slowing as the engine almost cut out)...this was all followed by a very strong gas smell. I tested it a few more times, and the action is consistent. I didn't see any fuel on the ground anywhere, but I also haven't gotten under the car yet to check it...I am very hesitant to start the car any more if there is a potential gas leak.

The car is a 1994 S500 coupe with about 95k miles on the clock. Please, give me any advice, and I plan on having a mechanic friend of mine come look at it later today. Thank you.