98 Cutlass Just cuts off ???

So after driving the car on the highway or anywhere that allows the engine to heat up. After driving for a while and the engine is hot i put the car in park and let it sit for about 1-2 mins the car will just shut off. before the car shuts off it will idle up..sputter a bit once or twice then go off.

it was suggested that.....i change the Coolant temperature sensor so i did and nothing changed...

Any ideas

98 cutlass but the engine is a 99 V6 3.1L

Check air filter.
Check fuel pressure, after letting your engine warm.
Check if the coil secondary bundle resistance is the same when engine is cold and hot. When engine is off, of course. Test pair by pair after removing spark wire.

Test also EGR system, especially DPFE sensor. You may need a service manual for this part.