Are there any codes? Having had one of these cars before, I remember having an issue with the intake air temperature sensor causing the car to run roughly, occasionally stall, and shift hard. Replaced it and that took care of it. It is in the image below.
Otherwise, take a good look at your vacuum lines and spark plug wires. Wear and tear on either can cause rough running and stalling.
Let us know.
Thursday, June 15th, 2017 AT 8:01 PM