Fuel System:
* Fuel Pump: A failing fuel pump might not provide enough pressure to the engine, leading to stalling, especially under load or when accelerating. This is a common culprit in older vehicles.
* Fuel Filter: A clogged fuel filter restricts fuel flow, causing similar symptoms to a failing fuel pump.
* Fuel Injector(s): Clogged or malfunctioning fuel injectors can prevent adequate fuel delivery to the engine.
* Fuel Pressure Regulator: A faulty regulator can cause incorrect fuel pressure, leading to stalling.
Ignition System:
* Distributor Cap and Rotor: Worn or cracked distributor cap and rotor can cause misfires and stalling.
* Ignition Coil: A failing ignition coil can't produce the necessary high voltage to ignite the fuel-air mixture.
* Spark Plugs and Wires: Worn, fouled, or damaged spark plugs and wires can prevent proper ignition. This is a relatively easy check.
* Crankshaft Position Sensor (CKP Sensor): This sensor tells the computer the engine's rotational speed. A faulty sensor can cause the engine to stall.
* Camshaft Position Sensor (CMP Sensor): Similar to the CKP sensor, a faulty CMP sensor can lead to stalling.
Other Potential Causes:
* Throttle Position Sensor (TPS): A faulty TPS provides incorrect information to the engine computer about throttle position, potentially leading to stalling.
* Mass Airflow Sensor (MAF Sensor): This sensor measures the amount of air entering the engine. A faulty MAF sensor can cause incorrect fuel mixture and stalling.
* Vacuum Leaks: Leaks in vacuum lines can disrupt the engine's operation and cause stalling. These can be tricky to find.
* Alternator: A failing alternator might not charge the battery adequately, leading to stalling if the battery voltage drops too low.
* Transmission Issues (Automatic): Problems within the automatic transmission, such as low fluid, a failing torque converter, or internal issues, can cause stalling.
* Computer Problems (PCM): While less common, a malfunctioning Powertrain Control Module (PCM) can cause a variety of issues, including stalling.
Troubleshooting Steps:
1. Check the basics: Start with the easiest checks: Examine the battery terminals for corrosion, check the spark plugs and wires, and inspect the distributor cap and rotor (if applicable).
2. Listen for unusual noises: Pay close attention to any unusual sounds coming from the engine, transmission, or fuel system.
3. Check engine codes: Use an OBD-II scanner (if your Blazer has one, many 1993s didn't) to read any diagnostic trouble codes (DTCs) stored by the computer. These codes can provide valuable clues.
4. Professional diagnosis: If you're not comfortable working on your vehicle, take it to a qualified mechanic for a proper diagnosis. They have tools and experience to pinpoint the problem more efficiently.
It's impossible to diagnose the exact cause without more information and a hands-on inspection. Start with the simpler checks, and systematically eliminate possibilities. Remember safety first – always disconnect the negative battery terminal before working on any electrical components.
