High-Probability Issues:
* Crankshaft Position Sensor (CKP Sensor): This sensor tells the computer the engine's rotational position. A failing CKP sensor will cause intermittent misfires, stalling, and no-start conditions. It's a common cause of these symptoms and relatively inexpensive to replace.
* Camshaft Position Sensor (CMP Sensor): Similar to the CKP sensor, but for the camshaft. A faulty CMP sensor can also lead to the same problems.
* Ignition Control Module (ICM): This module controls the ignition system's timing and spark delivery. Heat can cause ICM failure, leading to intermittent starting problems.
* Distributor Cap and Rotor: While you say you have spark, a failing distributor cap or rotor can cause weak or inconsistent spark, especially when the engine is hot. Cracks in the cap or worn rotor contacts are common causes.
* Heat-related issue: Many car parts behave differently when hot vs cold. Your issue sounds heat-related. The components listed above (especially the ICM) can fail more frequently at higher temperatures.
Less Likely, But Still Possible:
* Fuel Pump Relay: Though you say you have fuel, a failing relay might not consistently deliver power to the pump, leading to intermittent fuel delivery.
* Wiring Issues: Look for corroded or damaged wiring, especially in the areas around the distributor, sensors, and fuel system components. Heat can exacerbate wiring problems.
* Engine Coolant Temperature (ECT) Sensor: A faulty ECT sensor might give incorrect readings to the computer, causing it to adjust the fuel mixture improperly, leading to stalling.
Troubleshooting Steps:
1. Check the basics: Double-check that you *really* have fuel and spark. A weak spark might be present but insufficient for consistent running. Check fuel pressure.
2. Focus on heat: If the car starts fine cold, then dies when it gets hot, that strongly points to a heat-related problem.
3. Check for error codes: Use an OBD-II scanner to read any diagnostic trouble codes (DTCs) stored by the car's computer. This can give you valuable clues.
4. Visual Inspection: Carefully inspect the distributor cap, rotor, wires, and sensors for any signs of damage or corrosion.
5. Start with the CKP/CMP sensors: These are relatively easy to access and test, and are high probability culprits given your symptoms.
Recommendation: Given the intermittent nature and the "hours" before restarting, a heat-related issue in the ignition system is the most likely. Start by visually inspecting the distributor, then check the CKP sensor, and then the ICM. An OBDII scan is also extremely important. If you're not comfortable working on your car's electrical system, it's best to take it to a qualified mechanic.
