Car Stalls at Full Stops

Hello,

I drive a 2000 Suzuki Esteem, 1.8L, 70K miles. The car drives sluggish, as if it's being pulled. Sometimes the car will shake when coming to a complete stop and shut off. When trying to restart the car, it turns on and immediately shut back off. It will turn on and remain on after letting it sit for a few hours.

I've had my car towed twice to my mechanic, who states the car does not need a tune-up and can not seem to duplicate the problem. This morning, I had the same problem - the RPMs quickly dropped to zero and I quickly put the car on park and stepped on the gas to prevent it from shutting off.

I am afraid to drive it. Any suggestions would be greatly appreciated.