My 1990 Lumina 3.1 had the same problem and it was caused by the crank sensor.
with a key
how can i change the turn singal on a 1990 Chevy lumina
what make a 1990 Chevy. Lumina Car cut off when make a complete stop.
On my Chevy lumina it is located right by the gas take on the right side of the car.
The 194 3.1 only
with a crowbar
The 1990 has a chain. The 1991 has a belt.
It is right next to the fuel tank.