* Fuel pump relay or fuel pump itself: The pump might be overheating and failing to deliver fuel consistently. After an hour, it cools down enough to function again briefly. This is a common culprit for intermittent fuel delivery problems.
* Crankshaft Position Sensor (CKP sensor): These sensors are prone to failure, especially with age and heat. If the sensor fails when the engine reaches a certain temperature, it might prevent the engine from starting. It will often work again once it cools.
* Ignition coil or Ignition Control Module (ICM): Similar to the fuel pump, these components can overheat and fail intermittently, causing the engine to cut out. The heat buildup may be exacerbated by a failing ignition system.
* Mass Airflow Sensor (MAF sensor): A faulty MAF sensor can provide inaccurate readings to the engine computer, causing it to cut off fuel or ignition, possibly when it reaches a certain operating temperature.
* Engine Coolant Temperature (ECT) sensor: While it might seem unrelated, a faulty ECT sensor providing inaccurate readings to the Engine Control Unit (ECU) could lead to improper fuel mixture or timing, causing the engine to stall when hot. The ECU could be reacting to incorrect data thinking the engine is too hot and shutting things down as a precaution.
* Wiring harness issue: Heat can cause wires to short, especially in older vehicles. A short in the wiring could be responsible for the intermittent failure.
Troubleshooting Steps:
1. Check the fuel pump relay: Locate the fuel pump relay (consult your owner's manual) and try swapping it with a known good relay of the same amperage.
2. Check for error codes: Use an OBD-I scanner (you might need an adapter for your car's year) to retrieve any diagnostic trouble codes (DTCs). These codes can pinpoint the problem.
3. Monitor fuel pressure: Use a fuel pressure gauge to check the fuel pressure while the car is running and when it stops. A significant drop in pressure when the car stops could indicate a fuel pump or related component issue.
4. Inspect the ignition system: Visually inspect the ignition coil, wires, and distributor cap (if equipped) for signs of damage or wear.
5. Check the CKP sensor: This is more challenging and often requires some mechanical knowledge, but if other tests prove fruitless, this is a likely candidate.
6. Professional Diagnosis: If you can't diagnose the problem yourself, take your car to a qualified mechanic specializing in older vehicles. They have the tools and expertise to diagnose the issue more accurately.
This situation is likely due to a component overheating and failing temporarily. Addressing the heat-related issues is key to solving this problem. Remember safety first, always work on a cool engine, and if you are uncomfortable doing any of these steps yourself, seek professional help.
