* Fuel Delivery:
* Fuel Pump: The fuel pump might be weakening with heat. It could be struggling to maintain sufficient pressure when hot, leading to fuel starvation. This is a common culprit in older cars.
* Fuel Filter: A clogged fuel filter restricts fuel flow, and this restriction worsens under heat.
* Vapor Lock: The fuel lines might be absorbing heat, causing fuel vaporization and blocking fuel flow. This is more likely if the fuel lines are old and exposed to direct sunlight.
* Ignition System:
* Ignition Coil: The coil can overheat and fail to produce a strong spark when hot.
* Distributor Cap and Rotor: These parts can crack or develop carbon tracking with age and heat, leading to poor spark delivery.
* Ignition Wires: Worn or damaged ignition wires can cause poor spark delivery, especially when hot.
* Cooling System (Indirectly):
* Overheating: While the car restarts after cooling, a slightly overheating engine could be causing the problem indirectly. An overheating engine can impact various systems, including the ignition and fuel delivery. Check your coolant level, radiator, and thermostat. A faulty coolant temperature sensor could also be causing this.
* Engine Management (Less Likely on a Carbureted Model): While less likely on a carburetor-equipped 1984 Z28, there could be a faulty sensor (if it has electronic components) causing issues when heated.
Troubleshooting Steps:
1. Check Coolant Level and Temperature: Rule out overheating as a primary or contributing factor. Ensure the cooling system is functioning correctly.
2. Inspect Fuel System: Examine the fuel pump, fuel filter, and fuel lines for any signs of damage, leaks, or blockage. Consider replacing the fuel filter as a preventative measure. Look for signs of vapor lock (swelling fuel lines).
3. Test Fuel Pressure: If possible, use a fuel pressure gauge to measure the fuel pressure when the engine is hot. Low pressure confirms a fuel delivery problem.
4. Inspect Ignition System: Carefully examine the distributor cap, rotor, ignition coil, and ignition wires for any signs of wear, cracking, or damage. Replace any suspect components.
5. Check for Spark: Use an inline spark tester to confirm spark at each spark plug wire while the engine is hot (safely!).
6. Listen for Fuel Pump: You should hear the fuel pump hum when the ignition is turned on. A weak or failing pump will often hum faintly or not at all.
Important Note: Since the car restarts after cooling, the problem is likely heat-related. Focus on components that are most susceptible to heat damage. Working on a hot engine is dangerous; allow ample time for cooling before performing any checks. If you're not comfortable performing these checks yourself, take it to a qualified mechanic.
