Fuel System Issues:
* Dirty Fuel Filter: A clogged fuel filter restricts fuel flow, especially at idle when fuel demand is lower. This is a cheap and easy thing to check/replace first.
* Fuel Pump: A weak or failing fuel pump might not provide sufficient pressure at idle. You'll need a fuel pressure gauge to test this.
* Clogged Fuel Injector(s): Clogged injectors can prevent proper fuel delivery. This often requires professional cleaning or replacement.
* Vacuum Leaks in Fuel Lines: Leaks can disrupt fuel delivery and cause stalling. Inspect all fuel lines carefully.
Ignition System Issues:
* Distributor Cap and Rotor: Worn or corroded components can cause intermittent spark, leading to stalling. Inspect for cracks, corrosion, or wear.
* Ignition Coil: A failing ignition coil won't provide sufficient spark.
* Spark Plugs and Wires: Worn or fouled spark plugs and damaged wires can result in a weak or inconsistent spark.
* Crankshaft Position Sensor (CKP): This sensor tells the computer the engine's rotational speed. A failing CKP can cause stalling, especially at idle.
Air Intake System Issues:
* Mass Airflow Sensor (MAF): A dirty or faulty MAF sensor provides inaccurate air readings to the engine computer, leading to incorrect fuel mixture. Cleaning it is sometimes helpful.
* Vacuum Leaks in Intake Manifold: Leaks in the intake manifold system disrupt the air/fuel mixture. Inspect all vacuum lines and the intake manifold itself.
* IAC (Idle Air Control) Valve: This valve regulates air flow at idle. A dirty or faulty IAC valve can cause stalling. Cleaning it is often the first step, but it might need replacement.
Other Potential Issues:
* Throttle Position Sensor (TPS): A faulty TPS provides inaccurate throttle position information to the computer, affecting fuel delivery.
* Engine Coolant Temperature (ECT) Sensor: An inaccurate ECT sensor reading can cause the computer to adjust the fuel mixture improperly.
* Computer (ECM) Issues: While less common, a faulty engine control module can cause various problems, including stalling. This is usually diagnosed last.
Troubleshooting Steps:
1. Start with the easiest and cheapest: Check the fuel filter, spark plugs, wires, and distributor cap/rotor.
2. Listen for unusual sounds: Clicking from the fuel pump, ticking from the injectors, or hissing from vacuum leaks can provide clues.
3. Check engine codes: Use an OBD-I scanner (a specific one for the 1993 S10's system) to read any diagnostic trouble codes (DTCs). These codes can point to the specific problem.
4. Visual Inspection: Carefully inspect all hoses, wires, and connections for damage or leaks.
5. Professional help: If you are not comfortable working on your vehicle yourself, take it to a qualified mechanic for diagnosis and repair.
Remember safety first! Disconnect the negative battery terminal before working on any electrical components. If you're not familiar with automotive repair, seeking professional help is recommended.
