Things to Recheck and Areas Often Overlooked:
* Fuel Pump Pressure *and* Volume: You checked pressure, but did you check *volume*? A pump might deliver the right pressure but not enough fuel *flow*. A low fuel volume test should be done with a fuel pressure gauge attached, ideally while cranking and running. A weak pump might show good pressure at idle but fail under load.
* Fuel Filter: A clogged fuel filter restricts fuel flow, causing stalling, especially under acceleration. This is a cheap and easy component to replace.
* Crankshaft Position Sensor (CKP): This sensor tells the computer the position of the engine's crankshaft, crucial for proper ignition timing. A faulty CKP sensor will lead to stalling or misfires. It's relatively inexpensive and easy to replace, but it requires some mechanical knowledge.
* Camshaft Position Sensor (CMP): Similar to the CKP sensor, but for the camshaft. A faulty CMP sensor can cause similar issues.
* Ignition Control Module (ICM): This component controls the ignition system. A failing ICM can cause intermittent misfires and stalling. It's often overlooked.
* Distributor (if equipped): A 1992 Caravan *might* have a distributor, although it's less likely with a 6-cylinder. Check for worn distributor cap, rotor, or internal problems within the distributor itself (if applicable).
* Wiring and Connections: Inspect all wiring related to the fuel system, ignition system, and sensors for corrosion, breaks, or loose connections. A seemingly small wiring issue can cause major problems.
* Throttle Position Sensor (TPS): A faulty TPS tells the computer the wrong throttle position, leading to poor fuel delivery and stalling.
* Computer (PCM/ECM): Although less likely, a failing computer can cause intermittent problems and erratic behavior. This is usually a last resort diagnosis after checking everything else.
* Vacuum Leaks: Check all vacuum lines for cracks or leaks. A substantial leak will affect engine performance and can cause stalling.
* Intake Air Temperature Sensor (IAT): Provides the computer with air temperature data; a faulty sensor gives incorrect readings.
* Oxygen Sensor (O2 Sensor): While less likely to cause immediate stalling, a faulty O2 sensor can affect fuel mixture over time and contribute to the problem.
Troubleshooting Steps:
1. Start with the easy stuff: Replace the fuel filter.
2. Check wiring and connections: Visually inspect all wiring related to fuel, ignition, and sensors. Pay close attention to connectors at sensors.
3. Test the CKP and CMP sensors: These are common culprits. A mechanic can often test these with a scanner.
4. Check for vacuum leaks: Use a vacuum gauge or spray carb cleaner around vacuum lines while the engine is running. A change in idle indicates a leak.
5. Use a scan tool: A scan tool can read diagnostic trouble codes (DTCs) from the car's computer, which can pinpoint the issue. Even a basic OBD-I scan tool is helpful.
Important Note: If you're not comfortable working on your car's electrical and fuel systems, take it to a qualified mechanic. Improperly working on these systems can be dangerous. A mechanic with experience on older vehicles will have the knowledge and tools to diagnose the problem effectively.
