* Fuel Delivery Problems: This is a very common cause. Consider these possibilities:
* Fuel pump: A weak or failing fuel pump might not provide enough fuel under load (when you pump the throttle). The engine struggles and dies.
* Fuel filter: A clogged fuel filter restricts fuel flow, causing similar symptoms.
* Fuel injectors: Clogged or malfunctioning injectors can prevent proper fuel delivery. This is more likely to cause rough running at all times, but can be exacerbated under load.
* Low fuel pressure: Issues within the fuel pressure regulator can lead to insufficient fuel pressure.
* Ignition System Problems:
* Distributor cap and rotor: Worn or cracked components can cause misfires, leading to rough running and stalling.
* Ignition coil: A weak coil can fail to provide sufficient voltage to the spark plugs.
* Spark plugs and wires: Worn, fouled, or damaged spark plugs and wires can cause misfires.
* Vacuum Leaks: Vacuum leaks disrupt the engine's air/fuel mixture, leading to rough running and stalling. Check all vacuum lines and connections.
* Throttle Body Issues: Problems with the throttle body itself (especially if it's a throttle body injection system, common in some 1986 models):
* Throttle Position Sensor (TPS): A faulty TPS provides incorrect information to the engine's computer, leading to poor fuel/air mixtures.
* Dirty throttle body: A dirty throttle body can hinder airflow and disrupt the fuel/air mixture.
* Computer/ECM Issues: While less likely, a malfunctioning Engine Control Module (ECM) could cause erratic behavior. This is harder to diagnose without specialized tools.
* Air Intake System: Restrictions in the air intake system (dirty air filter, blocked intake) can starve the engine of air, leading to poor running.
Troubleshooting Steps:
1. Start with the easy checks: Inspect the air filter, check fuel level, visually examine the distributor cap and rotor for cracks or wear, and check the condition of the spark plug wires.
2. Fuel Pressure Test: This is crucial. A fuel pressure gauge will tell you if the fuel pump is delivering sufficient pressure.
3. Check for vacuum leaks: Use a vacuum gauge or spray carburetor cleaner around vacuum lines and connections while the engine is running. A change in engine RPM indicates a leak.
4. Check for codes: If your Corvette has a check engine light, use a code reader to retrieve diagnostic trouble codes (DTCs). This will provide valuable clues.
5. Ignition System Check: Test the ignition coil and spark plugs. You might need a spark tester for accurate assessment.
Important Note: Diagnosing car problems accurately requires experience and often specialized tools. If you're not comfortable working on your car's fuel and ignition systems, it's best to take it to a qualified mechanic. Trying to diagnose and fix these issues without the proper knowledge can be dangerous and potentially damage the engine further.
