Possible Culprits:
* Ignition System:
* Spark Plugs & Wires: Worn or fouled spark plugs and corroded or cracked wires can cause misfires, leading to rough running and stalling.
* Ignition Coil: A failing coil can deliver weak sparks, leading to intermittent misfires.
* Distributor Cap & Rotor: Cracks or buildup on the distributor cap or worn rotor can disrupt spark delivery.
* Fuel System:
* Fuel Pump: While you've replaced the pump, there's a chance it's still not delivering consistent fuel pressure. Check for leaks or a faulty pump.
* Fuel Lines: Cracked or clogged fuel lines can restrict fuel flow, causing problems.
* Fuel Filter: Even though you've replaced it, there might be a blockage further down the line.
* Carburetor: If your van has a carburetor, it could be experiencing problems like a sticking float or a clogged jet.
* Engine Management System:
* Sensors: Sensors like the oxygen sensor, temperature sensor, or MAP sensor (if equipped) can malfunction and cause incorrect engine operation.
* Vacuum Leaks: Small vacuum leaks can disrupt the airflow to the engine and lead to rough idling and stalling.
Troubleshooting Steps:
1. Check for Codes: If your van has a check engine light, read the codes with a scanner. This can provide valuable clues about potential problems.
2. Inspect Spark Plugs & Wires: Remove the spark plugs and check for signs of wear, fouling, or gaps outside of the recommended specifications. Inspect the wires for cracks or corrosion.
3. Test Ignition Coil: Use a spark tester or a multimeter to check the coil's output.
4. Inspect Distributor Components: Check the distributor cap for cracks or buildup. Inspect the rotor for wear or damage.
5. Test Fuel Pressure: Use a fuel pressure gauge to check the fuel pressure at the fuel rail. Make sure it's within the manufacturer's specifications.
6. Inspect Fuel Lines: Visually inspect fuel lines for cracks, leaks, or kinks.
7. Check for Vacuum Leaks: Use a vacuum gauge to test for leaks in the vacuum lines.
8. Inspect Carburetor (If Applicable): If your van has a carburetor, check the float level, jets, and other components for blockage or wear.
Additional Tips:
* Fuel Additives: Consider using a fuel system cleaner to help clean the injectors and fuel lines.
* Professional Mechanic: If you're unable to pinpoint the problem yourself, it's best to take your van to a qualified mechanic. They have specialized tools and experience to diagnose and repair these issues.
Remember: Always be cautious when working on your vehicle, and make sure to consult your owner's manual for specific instructions and safety precautions.
