Why does car stall when slowly turning into parking space?

If it isn't hard to turn the steering than you may have a vacuum leak. Sometimes a small vacuum leak can cause an engine to run differently and be more pronounced when the car is under more load like when using your powersteering in low speed manuevers. There are many ways to check for vauum leaks but the first is a visual inspecition looking for broken or collapsed vauum lines/hoses. Alex