* Fuel System Issues:
* Fuel pump: A weak or failing fuel pump might not be able to supply enough fuel under high demand (hard acceleration). This is a prime suspect.
* Fuel filter: A clogged fuel filter restricts fuel flow, leading to similar symptoms.
* Fuel injectors: Clogged or malfunctioning fuel injectors can prevent the proper amount of fuel from reaching the cylinders. They might be delivering insufficient fuel under pressure.
* Fuel pressure regulator: This component regulates fuel pressure; a faulty regulator can cause inconsistent fuel delivery.
* Ignition System Problems:
* Ignition coil: A failing ignition coil might not provide sufficient spark to all cylinders, leading to misfires and rough running, especially under load.
* Spark plugs and wires: Worn, fouled, or damaged spark plugs and wires can also cause misfires. This is a relatively inexpensive area to check first.
* Distributor cap and rotor (if applicable): Cracks or corrosion in these components can interrupt the spark delivery. (Less likely on a '94 Park Avenue, but still possible depending on engine type.)
* Air Intake System:
* Mass Airflow Sensor (MAF) sensor: A faulty MAF sensor provides inaccurate readings of air intake, causing the engine to run lean or rich, leading to hesitation and bucking.
* Throttle Position Sensor (TPS): A malfunctioning TPS provides incorrect information about the throttle position, disrupting the fuel/air mixture.
* Vacuum leaks: Leaks in vacuum hoses can disrupt the proper functioning of various engine systems, including fuel delivery and ignition timing.
* Transmission Issues (less likely): While less probable, a slipping or worn transmission could also contribute to bucking under acceleration. This is more likely to be accompanied by other transmission symptoms like slipping gears or delayed shifting.
* Other Potential Causes:
* Catalytic converter: A severely clogged catalytic converter can restrict exhaust flow, leading to poor performance and potentially stalling.
Troubleshooting Steps:
1. Check the basics: Start with the easiest and cheapest checks: inspect spark plugs and wires for wear, check the air filter for cleanliness, and look for any obvious vacuum leaks.
2. Diagnostic Codes: Use an OBD-II scanner to check for any diagnostic trouble codes (DTCs) stored in the engine control unit (ECU). These codes can point you directly to the problem area.
3. Professional Diagnosis: If you're not comfortable working on your car yourself, take it to a qualified mechanic. They have the tools and expertise to diagnose the problem accurately and efficiently. A proper diagnosis often involves more specialized equipment than the average DIYer has.
It's important to systematically investigate these potential problems, starting with the simplest and most common issues. Ignoring the problem could lead to further damage and more expensive repairs.
