Fuel System:
* Fuel pump relay: Heat can cause relays to fail intermittently. When hot, the relay might not be supplying power to the fuel pump.
* Fuel pressure regulator: A faulty regulator might be leaking fuel pressure when hot, leading to insufficient fuel delivery. This is a common culprit in these types of issues.
* Fuel injectors: While less common, injectors can become less efficient when heated, causing a lean condition that leads to stalling.
* Fuel filter: A clogged fuel filter restricts fuel flow, and this can be exacerbated by heat, causing problems after the engine is warmed up.
Ignition System:
* Ignition control module (ICM): The ICM is susceptible to heat damage. Failure often manifests as stalling after the engine reaches operating temperature. This is a prime suspect.
* Ignition coil: Similar to the ICM, heat can degrade the coil's performance, resulting in misfires and stalling.
* Distributor cap and rotor (if applicable): Although the LT1 is not a distributor-based ignition system, check for any possible issues within the ignition wiring harness. Arcing or corrosion due to heat can cause problems.
Cooling System (Indirectly):
* Overheating: While the car might not be obviously overheating (gauge reading normal), a small issue in the cooling system could cause localized overheating in critical components like the ICM or other engine sensors, leading to failure.
Other Possibilities:
* Mass airflow sensor (MAF): A faulty MAF sensor can provide inaccurate air readings, leading to a lean or rich fuel mixture, which can be more pronounced when hot.
* Throttle position sensor (TPS): A failing TPS can cause erratic idling and stalling, particularly when the engine is warm.
* Crankshaft position sensor (CKP): If the CKP is malfunctioning, it can prevent the engine from starting, more likely after heat exposure.
* Wiring harness: Heat can damage wiring harnesses, causing shorts or breaks. Inspect for any visible damage, especially in areas near the engine.
Troubleshooting Steps:
1. Check for Diagnostic Trouble Codes (DTCs): Use an OBD-I scanner to retrieve any stored codes. These codes can provide valuable clues.
2. Check fuel pressure: Measure the fuel pressure when the engine is hot. A significant drop in pressure points to a fuel system problem.
3. Inspect the ICM: Look for any signs of overheating or damage to the ICM.
4. Check the wiring harness: Visually inspect the wiring harness for any damage, corrosion, or loose connections, especially near heat sources.
5. Test the MAF sensor: If possible, test the MAF sensor with a multimeter or have it tested by a professional.
6. Test the TPS sensor: Similarly, test the TPS sensor.
7. Check for coolant leaks: Ensure there are no coolant leaks which could lead to localized overheating.
Recommendation: Given the symptoms, the ICM, fuel pressure regulator, and fuel pump relay are strong suspects. Having a mechanic experienced with LT1 engines diagnose and test these components would be the most effective course of action. Attempting to diagnose these issues without the proper equipment and knowledge can be time-consuming and potentially lead to further damage.
