Fuel System:
* Fuel Pump: A weak or failing fuel pump can't deliver enough fuel under high demand (acceleration). This is a common culprit in older cars. Listen carefully for the whirring of the pump when you turn the key to the "on" position (before starting). A weak or failing pump might make a weaker or different sound.
* Fuel Filter: A clogged fuel filter restricts fuel flow, leading to poor acceleration and sputtering. This is a relatively inexpensive part to replace and should be done regularly as part of preventative maintenance.
* Fuel Injectors: Clogged or malfunctioning fuel injectors can deliver an inconsistent fuel spray, causing a rough idle and poor acceleration. This often requires specialized tools and knowledge to diagnose and repair.
* Fuel Pressure Regulator: This regulates the fuel pressure in the system. A faulty regulator can cause either too much or too little fuel pressure, leading to poor performance.
* Throttle Position Sensor (TPS): This sensor tells the computer the position of the throttle. A faulty TPS can send incorrect signals, leading to poor fuel delivery and erratic performance.
Ignition System:
* Ignition Coil: A failing ignition coil might not provide sufficient spark to ignite the fuel-air mixture consistently, leading to misfires and sputtering.
* Spark Plugs and Wires: Worn, fouled, or damaged spark plugs and wires can prevent a strong spark, resulting in misfires and poor performance. This is a relatively easy check and replacement.
* Distributor Cap and Rotor (if applicable): Cracks or corrosion in the distributor cap and rotor can disrupt the spark delivery.
Air Intake System:
* Mass Airflow Sensor (MAF): A dirty or faulty MAF sensor provides inaccurate readings to the computer, causing it to adjust the fuel mixture improperly. Cleaning it (carefully!) might solve the problem.
* Air Filter: A severely clogged air filter restricts airflow, leading to a lean fuel mixture and poor performance. Replacing this is cheap and easy.
* Vacuum Leaks: Leaks in the vacuum lines can disrupt the air-fuel mixture, causing erratic performance. Inspect all vacuum lines for cracks or disconnections.
Other Possibilities:
* Catalytic Converter: A clogged catalytic converter can restrict exhaust flow, leading to reduced power and sputtering.
* Oxygen Sensor: A faulty oxygen sensor provides inaccurate information about the exhaust gases, causing the computer to adjust the fuel mixture incorrectly.
Troubleshooting Steps:
1. Start with the easy and cheap stuff: Check the air filter, spark plugs and wires.
2. Listen for the fuel pump: As mentioned above.
3. Check for vacuum leaks: Visually inspect all vacuum lines.
4. Consider a diagnostic scan: A professional mechanic can use a scan tool to read diagnostic trouble codes (DTCs) from the car's computer, which can pinpoint the problem more accurately.
Important Note: Since this is a performance car (Impala SS), you might have more advanced issues like a problem with the fuel injectors, or a mechanical problem within the engine itself. A professional mechanic specializing in older cars, or performance cars would be best to diagnose the problem correctly if the simpler solutions don't fix it.
