1. Fuel Pump Failure: A failing fuel pump may be unable to provide enough fuel to the engine, causing it to stall when under increased load.
2. Clogged Fuel Filter: A clogged fuel filter can restrict fuel flow, resulting in fuel starvation and engine stalling.
3. Faulty Ignition System: A faulty ignition coil, spark plug wires, or spark plugs can cause weak spark, leading to misfires and stalling.
4. Vacuum Leak: A vacuum leak can cause the engine to run lean, leading to stalling when under increased load.
5. Faulty Throttle Position Sensor (TPS): A faulty TPS can provide incorrect signals to the Engine Control Module (ECM), causing the fuel mixture to be incorrect, leading to stalling.
6. Clogged Catalytic Converter: A clogged catalytic converter can restrict exhaust flow, causing the engine to stall.
Diagnosis and Repair:
1. Fuel Pump: Check the fuel pump pressure using a fuel pressure gauge. If the pressure is low, the pump may need to be replaced.
2. Fuel Filter: Inspect the fuel filter for contamination and replace it if necessary.
3. Ignition System: Check the ignition system components, including the coil, spark plug wires, and spark plugs, for damage and replace any faulty parts.
4. Vacuum Leak: Use a smoke machine to detect vacuum leaks. Fix any found leaks by replacing cracked hoses or seals.
5. Throttle Position Sensor (TPS): Test the TPS using a multimeter to ensure it is sending the correct signals to the ECM. Replace if faulty.
6. Catalytic Converter: Check the catalytic converter for clogs. If it is clogged, it may need to be replaced.
Note: If the stalling only occurs when driving uphill, it is possible that the vehicle is not receiving enough cooling. Check the engine cooling system, including the radiator, coolant level, and water pump, to ensure that it is functioning properly.
