Possible Causes
* Fuel Pump: The most likely culprit is a faulty fuel pump. When you turn the ignition on, the pump primes the fuel system, allowing the engine to start. However, when you press the accelerator, the demand for fuel increases, and a failing pump might not be able to keep up, causing the engine to stall.
* Fuel Filter: A clogged fuel filter can restrict fuel flow, leading to a similar scenario as a faulty fuel pump.
* Fuel Lines: Cracked or blocked fuel lines can restrict fuel delivery, particularly under pressure when the engine is accelerating.
* Fuel Pressure Regulator: This component controls fuel pressure within the system. A faulty regulator might be causing low pressure, particularly under load.
* Air Intake System: A blockage in the air intake system (e.g., clogged air filter, blocked air intake hose) can cause a lean fuel mixture, leading to stalling.
Troubleshooting Steps
1. Check Fuel Pressure: This is the most crucial step. You'll need a fuel pressure gauge to test the pressure at the fuel rail. If the pressure drops significantly when you press the accelerator, it confirms a fuel delivery issue.
2. Inspect Fuel Lines: Look for any visible cracks, leaks, or blockages in the fuel lines.
3. Check Fuel Filter: Inspect the fuel filter for signs of clogging.
4. Test Fuel Pump: Listen for the fuel pump running when you turn the ignition on. You can also use a fuel pressure gauge to monitor pump output.
5. Inspect Air Intake: Make sure the air filter is clean and there are no obstructions in the air intake system.
Additional Notes:
* Spark Plugs: While you've already changed the spark plugs, they're not likely the primary cause of this issue. Spark plugs are essential for ignition but wouldn't cause the engine to stall specifically under acceleration.
* Engine Control Unit (ECU): A faulty ECU can cause various issues, including fuel delivery problems. However, this is less likely unless there are other symptoms, such as erratic engine behavior or warning lights.
Recommendation:
Unless you're experienced with car repairs, I highly recommend taking your Citroen Saxo to a qualified mechanic. They can perform a thorough diagnosis and identify the specific cause of the problem.
