* Fuel Delivery Issues:
* Fuel Pump: A weak fuel pump might not be able to supply enough fuel under high demand (hard acceleration). It might work fine at idle, but struggle when you need more fuel quickly.
* 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 engine during acceleration.
* Fuel Pressure Regulator: A faulty regulator could lead to incorrect fuel pressure, impacting performance.
* Ignition System Problems:
* Distributor Cap and Rotor: Worn or damaged components in the distributor can cause misfires, especially under load (hard acceleration).
* Ignition Coil: A weak or failing ignition coil may not provide sufficient spark energy for proper combustion under higher engine loads.
* Spark Plugs and Wires: Worn spark plugs or faulty spark plug wires can cause misfires, reducing power and leading to poor acceleration.
* Transmission Issues (Less Likely): While less likely to cause the problem *only* under acceleration, a slipping torque converter or other transmission problems could contribute to a lack of power.
* Air Intake System:
* Air Filter: A severely clogged air filter restricts airflow, limiting engine power.
* Vacuum Leaks: Leaks in the intake system can disrupt the air/fuel mixture, leading to poor performance. These are often more noticeable under load.
* Throttle Body Issues:
* Throttle Position Sensor (TPS): A faulty TPS can provide incorrect information to the engine computer, leading to poor fuel delivery and timing.
* Dirty Throttle Body: A dirty throttle body can restrict airflow, leading to reduced power.
Troubleshooting Steps:
1. Start with the basics: Check the air filter, and ensure there are no obvious vacuum leaks in the intake system.
2. Check the fuel system: Start with the fuel filter – it's the cheapest and easiest to replace. Consider checking fuel pressure if you have the tools and know-how.
3. Inspect the ignition system: Examine the distributor cap and rotor for wear or damage. Check the spark plugs and wires for wear, cracks, or corrosion.
4. Consider a diagnostic scan: If you have access to an OBD-I scanner (appropriate for a 1986 Corvette), it can read diagnostic trouble codes (DTCs) that can point to specific problems. OBD-I scanners for these cars are less common now, however.
Because the problem is load-dependent (only under hard acceleration), it's less likely to be a simple issue like a completely dead fuel pump (which would likely affect idle as well). A systematic approach, starting with the simpler checks, will likely lead you to the root cause. If you're not comfortable working on your car's systems, it's best to take it to a mechanic experienced with older Corvettes.
