Buick that stalls while driving

A have a 1994 Buick Regal that stalls while driving. It usually happens when I brake and 99% of the time it will immediately turn on when I put it in neutral (one time after a four hour drive, it took a minute to turn back on). This happens more if I am "in drive" especially slowing down off of a highway. Driving in 3rd and/or shifting to 3rd after getting off of a highway has decreased the amount of times this happens, but it has still stalled doing this as well. I have replaced the crank shaft sensor which has not worked, and I have had multiple mechanics look at it with no solutions. As a side story for solving this problem, the stalling started happening after I found a baby squirrel underneath the front of the car. The first time it happened, the squirrel was still in there, and it has happened ever since. I don't know if this is coincidental, but mechanics have looked for things that may have been chewed or moved and nothing was identified.

Welcome to AF!!

This sounds like the torque converter control solenoid is not releasing and causing the car to stall due to the converter being locked up. Take the car to a tranny shop and have them check it out. One thing you can try is the next time it starts to stall put the transmission into neutral and then back into drive after you come to a stop. If the solenoid is going bad you will need to get it replaced.

Is this a 3 speed automatic or 4 speed? If 3 speed, Then yes it could be the TCC solenoid, especially if it starts and then dies as soon as you put it in gear.....

I have a 4 speed. The car won't immediately stall when I put it in gear. Some days it will drive fine (in drive and in 3rd gear) and other days it will stall a lot. Even then though, if I put it in neutral and then turn the key, it will restart and I can continue driving. Is this still a solenoid problem?

Certainly sounds like it to me. Take it AAMCO and they will diagnose it for free. Cheaper than throwing parts at the problem.