1993 Buick Regal Stalls upon stopping

Engine Performance problem
1993 Buick Regal Automatic

have a 1993 Buick Regal that works fine in every significant way (a few minor issues, but nothing that affects its performance otherwise), except that every time I bring the car to a complete stop, i.E. At a stop sign, red light, etc, the car stalls and I have to restart the motor. The only way to combat this is to keep one foot on the brake and the other gently pressing the accelerator to keep the RPM's going a bit. This is fine, except it's annoying and, since the engine is kept spinning, it's burning more fuel than it should be.

I'm getting two opinions on the cause: 1) The throttle needs to be adjusted so the engine can idle without stopping completely (This comes from my friends and family), or 2) The coil pack is bad and needs to be replaced (This comes from my mechanic, who says it's normally $400, but he can get me a good used one for $40).

It's been run through the scanner for two previous problems, and it detected the coil pack was bad and one of the wires was no good, so we replaced the two of them. Now, my mechanic is saying that maybe the coil pack is still no good, but I'm beginning to doubt his integrity.

Thoughts?