Fuel System Problems:
* Fuel Pump: A failing fuel pump might be able to prime initially, allowing the engine to start, but then it can't keep up with the demand, causing the engine to stall. This is a very common cause.
* Fuel Filter: A clogged fuel filter restricts fuel flow, leading to similar symptoms.
* Fuel Pressure Regulator: A malfunctioning regulator can cause inconsistent fuel pressure, leading to starting problems and stalling.
* Clogged Fuel Injectors: Dirty injectors may not be able to deliver enough fuel consistently.
Ignition System Problems:
* Crankshaft Position Sensor (CKP): This sensor tells the computer the engine's rotational speed. A faulty sensor will prevent proper ignition timing, leading to stalling.
* Cam Position Sensor (CMP): Similar to the CKP sensor, but for the camshaft. A faulty CMP sensor can lead to similar issues.
* Ignition Coil: A failing coil might provide enough spark initially but then fail to sustain it.
* Distributor (if applicable): Older vehicles might have a distributor. Worn components inside can lead to intermittent spark. (Less likely in a 1998 but possible depending on the engine).
* Ignition Switch: A failing ignition switch might not provide consistent power to the ignition system.
Other Potential Problems:
* Battery: While a weak battery might crank slowly, it could still provide enough power to start, but then quickly lose enough power to stall. Check the battery terminals for corrosion.
* Alternator: Although the alternator charges the battery while the engine is running, a failing alternator might not be able to keep the battery charged after starting. The car might run for a few seconds before the voltage drops too low.
* Mass Airflow Sensor (MAF): A faulty MAF sensor can cause incorrect fuel/air mixtures, leading to stalling.
* Throttle Position Sensor (TPS): Similar to the MAF sensor, a faulty TPS can cause the engine to miscalculate the throttle position, leading to stalling.
* Computer Problems (PCM): Although less common, a failing PCM can cause a variety of issues, including stalling. This is usually diagnosed last.
* Vacuum Leaks: Leaks in the intake manifold or vacuum lines can disrupt the air/fuel mixture.
Troubleshooting Steps:
1. Check the obvious: Battery terminals, battery voltage, and any obvious loose connections.
2. Listen carefully: Listen for unusual noises while cranking or running. A whining fuel pump might be a clue.
3. Check engine codes: Use an OBD-II scanner to read any diagnostic trouble codes (DTCs) stored by the car's computer. This will give you valuable clues.
4. Check fuel pressure: A fuel pressure gauge will tell you if the fuel system is delivering adequate pressure. This usually requires a mechanic's tools and expertise.
It's difficult to diagnose this problem without more information. The best course of action is to have a qualified mechanic diagnose the problem using diagnostic tools. Attempting to diagnose and repair complex automotive issues without the proper tools and knowledge can be dangerous and costly.
