* Fuel System Problems: This is the most likely culprit given the symptoms. Consider these:
* Fuel Pump: A weak fuel pump might not deliver enough fuel under acceleration. Listen for a consistent hum from the pump when the ignition is turned on (but engine not running). A weak hum or no hum indicates a failing pump.
* Fuel Filter: A clogged fuel filter restricts fuel flow, causing sputtering and low power, especially under load.
* Fuel Injectors: Clogged or malfunctioning fuel injectors won't deliver the proper amount of fuel to the cylinders. This is common on older fuel-injected cars. They might need cleaning or replacement.
* Throttle Body: The throttle body might be dirty or the throttle position sensor (TPS) could be faulty. A dirty throttle body restricts airflow, impacting performance. A faulty TPS gives the engine the wrong fuel/air mixture information.
* Fuel Pressure Regulator: This regulates the fuel pressure in the system. A faulty regulator can lead to inconsistent fuel delivery.
* Ignition System Issues:
* Distributor Cap and Rotor: These components wear over time and can cause misfires, leading to sputtering and low power. Inspect them for cracks, corrosion, or excessive wear.
* Ignition Coil: A failing ignition coil might not provide enough spark to ignite the fuel-air mixture consistently.
* Spark Plugs and Wires: Worn spark plugs or cracked/worn spark plug wires can also cause misfires.
* Air Intake System:
* Air Filter: A severely clogged air filter restricts airflow to the engine, reducing power. Check and replace if necessary.
* Vacuum Leaks: Leaks in the vacuum lines can disrupt the engine's timing and fuel delivery, leading to poor performance.
* Other Possibilities (Less Likely):
* Catalytic Converter: A severely clogged catalytic converter can restrict exhaust flow, reducing engine power. This usually causes a significant loss of power and might be accompanied by other symptoms.
* Oxygen Sensor: While less likely to directly cause sputtering, a faulty oxygen sensor can lead to a poor air/fuel mixture, contributing to overall performance issues.
Troubleshooting Steps:
1. Check the basics: Air filter, fuel filter, spark plugs and wires, distributor cap and rotor. Replace anything that looks worn or damaged.
2. Listen for the fuel pump: Does it make a consistent hum?
3. Check for vacuum leaks: Inspect all vacuum hoses for cracks or loose connections.
4. Have a fuel pressure test done: This will determine if the fuel pressure is adequate.
5. Check for any diagnostic trouble codes (DTCs): If your car has a check engine light, get the codes read. This can help pinpoint the problem.
It's highly recommended to take your Cadillac to a mechanic experienced with older vehicles. They have the tools and expertise to diagnose and repair the problem effectively. Many of the problems listed require specialized tools and knowledge to properly diagnose and repair. Trying to fix these issues without experience could lead to further damage.
