1999 GMC Jimmy Stalling Issue

I have a 1999 GMC Jimmy 4.3l that came to me with a dying problem. The vehicle would die while driving. Sometimes it will fire right back up others you would have to wait a few minuets. We replaced the spark plugs, wires, cap, rotor, crankshaft position sensor, fuel pump, fuel filter, ignition coil and air filter. This made the vehicle run perfect and not die while running but its still dying while in park. When it dies it gives no warning, no lights, its just like you bumped the key and the engine dies. Can someone please help me with any ideas that might be causing this? Thank you!