Fuel System:
* Fuel Filter: A clogged fuel filter restricts fuel flow, especially under load. This is a cheap and easy first check. Replace it.
* Fuel Pump: A weak fuel pump might provide enough fuel at idle but struggle to keep up under acceleration. Listen for a humming sound from the tank – a weak or failing pump may make a different noise than usual. Fuel pressure testing is needed to confirm.
* Fuel Injectors: Clogged or malfunctioning fuel injectors can prevent sufficient fuel delivery. Cleaning them (or replacing if necessary) is a more involved process.
* Mass Airflow Sensor (MAF): A dirty or faulty MAF sensor provides inaccurate air readings to the computer, leading to poor fuel mixture and performance issues. Cleaning it (carefully!) is often effective. If cleaning doesn't work, replacement is likely needed.
* Throttle Position Sensor (TPS): A faulty TPS sends incorrect throttle position information to the computer, leading to incorrect fuel delivery. Testing with a multimeter is necessary.
Ignition System:
* Spark Plugs and Wires: Worn or fouled spark plugs and damaged wires can cause misfires, resulting in power loss. Replace them if they are old or show signs of wear.
* Distributor Cap and Rotor (if applicable): Cracks or corrosion in these components can interrupt the spark, causing misfires. Inspect them for damage.
* Ignition Coil: A weak or failing ignition coil might not produce a strong enough spark under load.
Other Potential Issues:
* Catalytic Converter: A clogged catalytic converter will restrict exhaust flow, severely limiting engine power.
* Intake Manifold Leaks: Vacuum leaks in the intake manifold will significantly affect performance. Inspect all vacuum hoses and connections.
* Exhaust Leaks: Leaks before the catalytic converter can reduce power and alter the fuel mixture.
* EGR Valve: A sticking or faulty EGR valve can cause performance problems.
Troubleshooting Steps:
1. Check the basics: Start with the simplest and cheapest fixes: fuel filter, spark plugs, wires.
2. Listen to the engine: Pay attention to unusual noises like ticking, knocking, or whining sounds.
3. Check engine codes: Use an OBD-I scanner (specific to your vehicle's year) to retrieve any diagnostic trouble codes (DTCs) stored in the computer. These codes can provide valuable clues.
4. Visual inspection: Carefully inspect all vacuum hoses, connections, and components for any signs of damage or leaks.
5. 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 properly diagnose the problem.
Important Note: The fact that it idles fine but bogs down under acceleration strongly suggests a problem with fuel delivery or ignition under load, rather than a major engine mechanical problem. However, a thorough diagnosis is crucial to pinpoint the exact cause. Don't continue driving the car extensively while it's experiencing this problem, as it could cause further damage.
