1. Heat Soak Issues:
* Crankshaft Position Sensor (CKP Sensor): This is a very common culprit in older GM vehicles. When it gets hot, it can fail, preventing the engine from starting. The sensor is relatively inexpensive and easy to replace. After replacing it, make sure you have the correct sensor for your application.
* Ignition Control Module (ICM): Located near the distributor, the ICM can overheat and fail. Similar to the CKP sensor, this is a frequent cause of heat-soak starting problems. It's also relatively inexpensive and replaceable.
* Mass Airflow Sensor (MAF Sensor): A faulty MAF sensor can give incorrect readings to the computer, leading to erratic operation and stalling. While less likely to be directly heat-related in the way the CKP and ICM are, a hot engine can exacerbate any existing issues.
* Fuel Pump Relay: Heat can cause the relay to stick or fail, preventing the fuel pump from working. Try swapping the fuel pump relay with another relay of the same amperage (be cautious of mismatching and causing damage!).
2. Other Potential Issues (less likely to be directly heat-related, but still possible):
* Fuel Pump: A weak fuel pump might not deliver enough fuel when the engine is hot. This would require testing fuel pressure.
* Throttle Position Sensor (TPS): A malfunctioning TPS can cause erratic idle and stalling.
* Engine Coolant Temperature (ECT) Sensor: A faulty ECT sensor can provide incorrect readings to the engine control module (ECM), leading to poor fuel mixture and stalling.
* Distributor Cap and Rotor: Inspect for cracks, corrosion, or worn contacts. These can cause misfires and stalling.
* Spark Plugs and Wires: Worn or faulty spark plugs and wires can also cause intermittent stalling.
* ECM Issues (rare): While less common, a problem with the ECM itself is possible. This is usually a last resort diagnosis.
Troubleshooting Steps:
1. Check for Error Codes: Use an OBD-I scanner (specific to 1995 vehicles) to read any diagnostic trouble codes (DTCs) stored in the ECM. These codes can provide valuable clues.
2. Visual Inspection: Inspect the ignition system components (wires, cap, rotor, plugs) for signs of damage or wear.
3. Test the CKP Sensor: This is often the first step after a code scan if no obvious problems are seen. You might need a multimeter to test resistance.
4. Test Fuel Pressure: Measure fuel pressure using a fuel pressure gauge to ensure the pump is delivering adequate fuel.
5. Relay Swap: Try swapping relays to see if that solves the problem.
6. Heat Soak Test: Let the car run until it's fully warmed up. Then shut it off and try starting it again after 15-30 minutes. If it won't start right away, this points towards a heat soak issue.
7. Professional Diagnosis: If you're not comfortable performing these tests or the problem persists, take the car to a qualified mechanic specializing in older vehicles. They have the tools and expertise to diagnose and repair more complex problems.
Important Note: Always disconnect the negative battery terminal before working on any electrical components. Improperly working on the car's electrical system can lead to serious injury. Safety first!
