* Cooling System Problems: This is the most likely culprit. When the engine heats up, several things can go wrong:
* Thermostat Stuck Closed: Prevents coolant from circulating properly, leading to overheating. The engine may run poorly or stall due to excessive heat.
* Water Pump Failure: If the water pump isn't circulating coolant effectively, the engine will overheat. This can cause the engine to overheat, leading to the shaking and stalling.
* Low Coolant Levels: This is a basic but crucial problem. Lack of coolant means inadequate heat dissipation, leading to overheating and the subsequent problems. Check for leaks!
* Radiator Issues: A clogged radiator, damaged fins, or a malfunctioning radiator fan (especially if it only runs when hot) will prevent efficient cooling.
* Head Gasket Failure: A blown head gasket allows coolant to leak into the cylinders or vice-versa. This will cause overheating, white smoke from the exhaust, and potentially a milky substance in the engine oil. This is a serious problem.
* Ignition System Issues: Heat can exacerbate problems in the ignition system:
* Ignition Coil Failure: Coils can weaken with heat, leading to misfires, rough running, and stalling.
* Worn Spark Plug Wires: Heat can cause deterioration in the insulation of spark plug wires, resulting in misfires and poor performance.
* Distributor Cap and Rotor (if applicable): Cracks or carbon buildup can worsen with heat, causing erratic spark delivery.
* Fuel System Problems:
* Fuel Pump Failure: A failing fuel pump might struggle to deliver sufficient fuel as the engine heats up, leading to stalling. This is less likely to cause shaking *before* stalling.
* Fuel Injector Issues: Although less common, a fuel injector could become less efficient or fail when hot.
* Sensor Problems: Several sensors provide critical information to the engine's computer:
* Temperature Sensors: An inaccurate coolant temperature sensor can provide false information to the engine's computer, leading to incorrect fuel mixture and timing adjustments, especially when hot.
* Mass Airflow Sensor (MAF) or Throttle Position Sensor (TPS): While less directly related to heat, these sensors can malfunction and worsen with increased engine temperatures.
Troubleshooting Steps:
1. Check coolant level: This is the easiest first step. Low coolant is a significant indicator.
2. Inspect for leaks: Look carefully around the radiator, hoses, water pump, and engine block for any signs of coolant leaks.
3. Feel the radiator hoses: When the engine is running, the upper hose should be hot and the lower hose should be warm. If both are cold or only the upper is hot, there's likely a cooling system problem.
4. Listen for the radiator fan: Does it turn on when the engine gets hot? If not, it may be faulty.
5. Check the engine oil: Look for a milky or mayonnaise-like substance, indicating a potential head gasket problem.
It's highly recommended to have a mechanic diagnose the issue. Ignoring overheating can lead to catastrophic engine damage. The symptoms you describe suggest a serious problem that shouldn't be delayed. The cooling system should be thoroughly investigated first.
