* Heat soak issues: Older cars can experience heat soak, where the engine compartment gets excessively hot. This can affect various sensors and components, leading to intermittent failures. The 30-minute cooling-off period suggests this is a strong possibility. Look for things like a failing cooling fan, low coolant, or restricted airflow around the engine.
* Ignition system: Even with a new crankshaft sensor, other ignition components can fail intermittently. Consider:
* Ignition coil: A failing coil can cause misfires or complete engine failure, especially when hot.
* Ignition module: This controls the ignition coil's operation. A failing module can produce similar symptoms.
* Spark plugs and wires: While less likely if the car runs fine otherwise, worn or damaged spark plugs or wires can cause intermittent problems that worsen with heat.
* Fuel system: Issues here could manifest similarly:
* Fuel pump: A weak or failing fuel pump might provide sufficient pressure when cold, but struggle when hot.
* Fuel filter: A clogged fuel filter restricts fuel flow, potentially leading to stalling, especially under load.
* Fuel pressure regulator: This regulates fuel pressure within the system. A faulty regulator can lead to inconsistent fuel delivery.
* Mass Airflow Sensor (MAF) Sensor: A faulty MAF sensor provides incorrect information to the engine's computer, leading to poor running or stalling. Heat can exacerbate this.
* Computer (PCM): While less common, a failing PCM (Powertrain Control Module) could be causing the intermittent problem. This is more difficult to diagnose and requires specialized testing equipment.
* Wiring harness: Look for any signs of damaged, corroded, or loose wiring, especially in areas that get hot. A short circuit or break in the wiring could cause the engine to die.
Troubleshooting Steps:
1. Check for diagnostic trouble codes (DTCs): Use an OBD-II scanner to read any stored trouble codes. This can provide valuable clues to the problem's source.
2. Inspect the fuel system: Check the fuel pressure, examine the fuel filter, and listen for the fuel pump's operation.
3. Inspect the ignition system: Visually inspect the coil, wires, and spark plugs for signs of damage.
4. Check for heat soak: Observe the engine temperature and cooling system operation.
5. Monitor the MAF sensor (If Equipped): See if you can monitor its readings with a scanner while the engine is running, paying close attention to its readings just before and during the failure.
Because the problem persists after the crankshaft sensor replacement, a professional mechanic with diagnostic tools is likely needed to pinpoint the exact cause. Don't continue driving the car if it's dying unexpectedly, as it's a safety hazard.
