High-Probability Issues:
* Fuel Pump: This is a prime suspect. The van might have enough fuel pressure to crank, but not enough to sustain running under load. The fuel pump struggles as it ages, and the final exertion of pulling into the driveway could have been the straw that broke the camel's back. Listen carefully near the fuel tank – you might hear a faint whine when the ignition is turned on. A fuel pressure test is essential here. A mechanic can perform this test quickly.
* Crankshaft Position Sensor (CKP) or Cam Position Sensor (CMP): These sensors tell the engine's computer the position of the crankshaft and camshaft. A failing sensor can cause erratic running, loss of power, and stalling, especially under load. These are relatively inexpensive to replace.
* Fuel Filter: A clogged fuel filter restricts fuel flow, leading to similar symptoms. This is a cheap and easy part to replace, so it's worth checking.
* Ignition System (Distributor, Spark Plugs, Wires, Coil): A weak spark, caused by worn components in the ignition system, can cause rough running and stalling, especially under load. Inspect the spark plugs and wires for wear or damage. A failing distributor (if your van has one) or coil is less common but possible.
* Throttle Position Sensor (TPS): A faulty TPS can send incorrect information to the engine computer, leading to poor performance.
Less Likely (But Still Possible) Issues:
* Mass Airflow Sensor (MAF): This sensor measures the amount of air entering the engine. A malfunctioning MAF can cause a lean fuel mixture, resulting in rough running and poor performance.
* Vacuum Leaks: A leak in the vacuum system can disrupt the engine's timing and fuel delivery.
* Fuel Injectors: Clogged or faulty injectors can cause inconsistent fuel delivery.
Troubleshooting Steps:
1. Check for Obvious Issues: Look for any loose vacuum hoses, damaged wires, or anything visibly amiss.
2. Fuel Pressure Test: This is the most crucial step. A mechanic can do this easily and will quickly determine if the fuel pump is the issue.
3. Spark Test: Check for spark at the spark plugs. A weak spark points to a problem in the ignition system.
4. Listen for Unusual Noises: Pay attention to any unusual noises coming from the engine compartment. A grinding or whining sound could indicate a failing component.
Recommendation:
Unless you have significant automotive experience, taking your van to a qualified mechanic is highly recommended. Diagnosing these issues accurately often requires specialized tools and knowledge. Trying to fix it yourself without the right tools and diagnostics could lead to further damage or unnecessary expense. The fuel pressure test is a good starting point for the mechanic.
Providing more details about the van's history (recent maintenance, known issues) might help narrow down the possibilities further.
