Stalls and will not start for extended period of time

Welcome to temperature

The first thing I would suggest is to check for diagnostic trouble codes. This vehicle has an OBD1 system and you can check for codes at home. All you will need is either a short jumper wire or I have even used a paper clip. Here is a link that explains how it is done:

https://www.2carpros.com/articles/buick-cadillac-chevy-gmc-oldsmobile-pontiac-gm-1983-1995-obd1-code-definitions-and-retrieval-method

Do this and let me know what you find.

Based on your description, the first thought that comes to mind is the crankshaft position sensor is going bad. First, take a look through these two links:

https://www.2carpros.com/articles/how-a-crank-shaft-angle-sensor-works

https://www.2carpros.com/articles/symptoms-of-a-bad-crankshaft-sensor

As you can see, the sensor can cause stalling, no start when hot, and so on. Now to test the sensor, what you need to do is see if there is ignition spark to the spark plugs. Here is a link that shows how this is done. Also, you will need to check this when the engine refuses to start.

https://www.2carpros.com/articles/how-to-test-an-ignition-system

If you find there is no spark, then I would suggest replacement of the sensor. Here is a link that shows how in general one is replaced:

https://www.2carpros.com/articles/crankshaft-angle-sensor-replacement

Here are the directions specific to your vehicle. The attached directions correlate with the directions.

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Camshaft And Crankshaft Position Sensors
pic 1

Remove or Disconnect:
1. Disconnect negative battery cable
2. Remove serpentine belts from crankshaft pulley
3. Properly raise and support vehicle
4. Remove right front tire and wheel assembly
5. Remove right inner fender access cover
6. Using 28 mm socket, remove crankshaft harmonic balancer retaining bolt

Crankshaft Balancer With Interrupter Rings
pic 2

7. Using special tool J38197, remove crankshaft harmonic balancer

Crankshaft Position Sensor Shield
pic 3

8. Remove crankshaft position sensor shield
9. Disconnect sensor electrical connector

Crankshaft Sensor
pic 4

10. Remove sensor from block face

Install or Connect:
1. Install crankshaft position sensor to block face
2. Tighten bolts
Torque Value: 20-40 Nm (14-28 lb ft)
3. Install crankshaft position sensor shield
4. Connect electrical connector
5. Install balancer on crankshaft
6. Apply thread sealer GM #1052080 or equivalent to threads of crankshaft balancer bolt
Torque Value: 150 Nm + 76° (110 lb ft + 76°)
7. Install inner fender shield
8. Install tire and wheel assembly
Torque Value: 140 Nm (104 lb ft)
9. Lower vehicle
10. Install serpentine belt
11. Connect negative battery cable

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Let me know what you find or if you have other questions.

Take care,
Joe