Fuel System Problems:
* Fuel pump: A failing fuel pump can't deliver enough fuel to the engine, leading to stalling. This is a common issue in older cars.
* Fuel filter: A clogged fuel filter restricts fuel flow, causing similar symptoms to a failing fuel pump.
* Fuel pressure regulator: A malfunctioning regulator can cause inconsistent fuel pressure, leading to stalling or cutting off.
* Bad fuel injectors: Clogged or failing fuel injectors might not deliver fuel properly to the cylinders.
Ignition System Problems:
* Crankshaft Position Sensor (CKP): This sensor tells the engine's computer where the crankshaft is positioned. A faulty sensor will prevent the engine from running.
* Cam Position Sensor (CMP): Similar to the CKP, a faulty CMP sensor disrupts the engine's timing and can cause stalling.
* Ignition coil: A failing ignition coil can prevent a cylinder or multiple cylinders from firing.
* Distributor cap and rotor (if applicable): These components, common in older vehicles, can wear out, causing intermittent or complete engine failure. The 1998 Deville might use a distributor or a coil-on-plug system, so this is important to know.
* Ignition switch: A problem with the ignition switch itself can interrupt the electrical flow to the engine.
Electrical System Problems:
* Alternator: A failing alternator can't recharge the battery, and eventually the battery will die, causing the car to stall.
* Battery: A weak or dead battery can prevent the engine from starting or keep it from running consistently.
* Wiring issues: Corrosion, loose connections, or damaged wiring harnesses can interrupt the electrical signals needed for the engine to run.
Other Potential Causes:
* Throttle Position Sensor (TPS): This sensor tells the computer the throttle position. A faulty sensor can cause erratic engine behavior.
* Mass Airflow Sensor (MAF): This sensor measures the amount of air entering the engine. A faulty MAF sensor can cause the engine to run lean or rich, leading to stalling.
* Computer (PCM): While less common, a failing engine control module (PCM) can cause a variety of problems, including stalling.
* Overheating: An overheating engine can cause the computer to shut down the engine to prevent damage. Check coolant levels and look for signs of leaks.
Troubleshooting Steps:
1. Check the obvious: Battery voltage, coolant levels, and for any obvious signs of damage or leaks.
2. Check for error codes: Use an OBD-II scanner to read any diagnostic trouble codes (DTCs) stored in the car's computer. This is often the best place to start.
3. Professional Diagnosis: If you're not comfortable working on your car yourself, take it to a qualified mechanic for diagnosis and repair. They have the tools and expertise to pinpoint the problem efficiently.
It's crucial to have the car diagnosed professionally to determine the exact cause. Attempting repairs without proper knowledge can lead to further damage or injury.
