* Crankshaft Position Sensor (CKP): This sensor is crucial for the engine's timing. Heat can cause it to malfunction, leading to stalling. After cooling overnight, it might function well enough to start again, only to fail once it heats up during driving.
* Camshaft Position Sensor (CMP): Similar to the CKP sensor, the CMP is vital for engine timing. Heat-related issues can cause the same intermittent stalling problems.
* Ignition System: This includes the ignition coil, ignition module, and spark plug wires. A failing component might work intermittently when cool but fail under heat stress. Cracked distributor cap or worn rotor could also be involved.
* Coolant Temperature Sensor (CTS): This sensor tells the engine's computer the coolant temperature. A faulty CTS can lead to incorrect fuel mixture and timing adjustments, especially when the engine is hot. The incorrect mixture could cause stalling.
* Mass Airflow Sensor (MAF): A dirty or failing MAF sensor provides inaccurate information about the air intake, leading to a lean or rich fuel mixture. Heat can exacerbate these issues.
* Fuel Pump: While less likely to be directly related to the overnight cool-down, a weak fuel pump that struggles under heat might only provide enough pressure when cool, resulting in stalling after the engine is warmed up. Listen carefully near the fuel tank for unusual noises when the key is turned to "on" (before cranking).
* Vacuum Leaks: Heat can cause rubber hoses and vacuum lines to degrade, leading to vacuum leaks. This can disrupt the engine's operation and cause stalling, particularly under heat.
* Electrical Connections: Corrosion or loose connections can cause intermittent problems, especially when subjected to temperature changes.
Troubleshooting Steps:
1. Check for trouble codes: Use an OBD-II scanner to read any diagnostic trouble codes (DTCs) stored in the car's computer. These codes can pinpoint the problem. A 1995 Cavalier may require a scanner specifically designed for older OBD-I systems.
2. Visual Inspection: Check all vacuum lines, hoses, wiring, and connectors for cracks, damage, or corrosion.
3. Start with the easy checks: Replace the spark plugs and wires as a preventative measure. They're relatively inexpensive and a common cause of ignition issues.
4. Test the sensors: A mechanic can test the CKP, CMP, CTS, and MAF sensors to check their output. You can also attempt a visual inspection of these for damage or loose connections.
5. Consider the fuel system: If other areas prove to be fine, addressing potential issues with the fuel pump or fuel filter is the next step.
It's best to consult a qualified mechanic for proper diagnosis and repair. They have the tools and expertise to accurately identify the faulty component and safely fix the problem. Attempting repairs without proper knowledge could lead to further damage.
