Possible Causes:
* Fuel Pump: The fuel pump is responsible for delivering fuel from the tank to the engine. If it's failing, you won't get enough fuel to run properly.
* Fuel Filter: A clogged fuel filter can restrict fuel flow, causing stalling and difficulty starting.
* Fuel Injectors: Clogged or malfunctioning fuel injectors can prevent the proper amount of fuel from being delivered to the cylinders.
* Fuel Pressure Regulator: This component regulates fuel pressure within the system. If it's faulty, it can lead to inconsistent fuel delivery.
* Fuel Lines: Cracked, leaking, or blocked fuel lines can interrupt fuel flow.
* Ignition System (even though you checked spark): While you've confirmed spark, a faulty ignition system can sometimes affect fuel delivery indirectly (e.g., a weak spark could cause incomplete combustion, affecting fuel demand).
Troubleshooting Steps (Safety First!):
1. Safety First!
* Turn off the engine and allow it to cool completely.
* Avoid working on the fuel system while the engine is hot or running. Gasoline is flammable!
2. Check Fuel Pressure:
* Use a fuel pressure gauge (available at auto parts stores) to measure the pressure at the fuel rail.
* Compare the reading to the specifications in your service manual or online.
3. Inspect Fuel Lines:
* Visually examine all fuel lines for cracks, leaks, or kinks. Replace any damaged lines.
4. Check Fuel Filter:
* Locate the fuel filter (often near the fuel tank or engine).
* Replace the filter if it's dirty or clogged.
5. Test Fuel Injectors:
* This requires specialized equipment and knowledge. It's often best to take it to a mechanic.
6. Inspect Fuel Pump:
* Listen for the fuel pump running when you turn the ignition key to "on" (not start). If you don't hear it, it's likely failed.
* Access the fuel pump (it might be in the tank or mounted near the engine).
7. Consider Other Possibilities:
* Engine Control Unit (ECU): If the fuel system components are all working, there might be a problem with the ECU that controls them.
* Electrical Connections: Loose or corroded electrical connections in the fuel system can cause issues.
Additional Tips:
* Consult your owner's manual or a Mercedes-Benz repair manual for specific troubleshooting steps and diagnostic information related to your model.
* Seek professional help: If you're not comfortable working on fuel systems, it's best to take your car to a qualified mechanic.
* Don't overlook the basics: Check for loose or disconnected fuel lines, vacuum leaks, and other common problems.
Remember, working on fuel systems can be dangerous. If you're unsure about any aspect of the troubleshooting process, it's always best to seek professional assistance.
