1. Fuel System:
* Fuel pump: The pump might be weak or failing, unable to provide sufficient fuel pressure to keep the engine running once the initial starting fuel is used. Listen for the pump's whirring sound when you turn the key to the "on" position (before cranking). A fuel pressure gauge test is the definitive way to check this.
* Fuel filter: A clogged fuel filter restricts fuel flow. It's a cheap and easy part to replace.
* Fuel injectors: Clogged or faulty injectors might not deliver enough fuel. This is harder to diagnose without specialized tools.
* Fuel delivery lines: Check for cracks, leaks, or kinks in the fuel lines.
2. Ignition System:
* Distributor cap and rotor: Cracks, corrosion, or worn contacts in the distributor cap and rotor can interrupt the spark. Inspect them carefully.
* Spark plugs and wires: Worn or fouled spark plugs or damaged wires can prevent consistent ignition. Check for gaps and condition.
* Ignition coil: A failing coil won't provide sufficient voltage for consistent sparking.
* Ignition control module (ICM): This module controls the ignition system; a faulty ICM can cause intermittent or complete failure.
3. Air Intake System:
* Air filter: A severely clogged air filter restricts airflow, leading to poor running or stalling.
* Vacuum leaks: Cracks or holes in vacuum hoses can disrupt the engine's air/fuel mixture. Inspect all vacuum lines visually.
4. Sensors:
* Crankshaft position sensor (CKP): This sensor tells the computer the engine's rotational speed. A faulty sensor can prevent the engine from running consistently.
* Throttle position sensor (TPS): This sensor tells the computer the throttle position. A faulty TPS can cause erratic idling or stalling.
* Mass airflow sensor (MAF): This sensor measures the amount of air entering the engine. A faulty MAF can cause a lean or rich fuel mixture, leading to stalling. (Less likely on a '89, but possible)
5. Other Potential Issues:
* Idle air control (IAC) valve: This valve controls the idle speed. A dirty or faulty IAC valve can cause stalling.
* Computer/ECU problems: Though less common, a failing engine control unit (ECU) can cause a variety of problems, including stalling.
* Alternator: While it's less likely to directly cause stalling immediately after starting, a failing alternator might not be providing enough power to the ignition system after the initial charge from the battery is used.
Troubleshooting Steps:
1. Start with the easiest checks: Air filter, fuel filter, visual inspection of vacuum lines, distributor cap and rotor, spark plug wires.
2. Listen for the fuel pump: Does it prime when you turn the key?
3. Check for any error codes: While less common on 1989 models, a check engine light might indicate a problem. If present, you may need an OBD1 code reader (specific to that year).
4. Get help from a mechanic: If you're not comfortable working on your car's systems, have a qualified mechanic diagnose the problem. It's often more efficient and safer.
Remember safety first! Disconnect the negative battery terminal before working on any electrical components. If you're unsure about any step, seek professional help.
