Check the spark plugs and wires: Worn-out spark plugs or faulty spark plug wires can cause misfiring and stalling. Make sure the spark plugs are in good condition and properly gapped, and that the spark plug wires are securely connected.
Check the fuel filter: A clogged fuel filter can restrict fuel flow to the engine, causing it to run lean and misfire. Replace the fuel filter if it is dirty or clogged.
Inspect the fuel pressure: Low fuel pressure can also cause the engine to run lean and misfire. Use a fuel pressure gauge to check the fuel pressure and compare it to the manufacturer's specifications. If the fuel pressure is low, it could be due to a faulty fuel pump or a clogged fuel line.
Check the ignition coil: A faulty ignition coil can prevent the spark plugs from firing properly, causing misfiring and stalling. Test the ignition coil with an ohmmeter or replace it with a known-good coil.
Check the distributor cap and rotor (if applicable): A worn-out distributor cap or rotor can cause misfires and stalling. Make sure the distributor cap is in good condition and the terminals are clean and free of corrosion. Also check the rotor for cracks or damage and make sure it is seated properly.
Check the throttle position sensor (TPS): A faulty TPS can cause the engine to run lean or rich, which can cause misfiring and stalling. Test the TPS with a multimeter or replace it with a known-good sensor.
Have the engine scanned for trouble codes: Your vehicle may have stored trouble codes that can help you identify the cause of the problem. Use an OBD-II scanner to scan for trouble codes and research their meanings to get more information.
Note: If the problem is severe or you are unable to diagnose and fix it yourself, it is recommended to take your vehicle to a qualified mechanic for further inspection and repair.