Cuts Out/Misses

SYMPTOM DESCRIPTION:

Steady pulsation or jerking that follows engine speed, usually more pronounced as engine load increases. The exhaust has a steady spitting sound at idle or low speed.


POSSIBLE CAUSE ACTION



IGNITION SYSTEM MALFUNCTION - Scope check Ignition System

- Perform a cylinder balance test. Repair misfiring cylinders as necessary
- Check IGNITION COIL for proper output voltage.

- Check SPARK PLUGS for proper spark duration. Remove spark plugs, check for fuel fouled plugs, cracks, wear, improper gap, burned electrodes, or heavy deposits. Replace as necessary.

- Check SECONDARY CIRCUIT for abnormal firing Kv, crossfire between spark plugs (distributor cap, spark plug wires), and proper plug wire routing.

- Check IGNITION TIMING for excessive spark advance or retard.



ENGINE MECHANICAL MALFUNCTION - Check COMPRESSION Perform a compression check, and cylinder leakage test, look for sticking or leaking valves.

- If compression readings are low or inconsistent check for improper valve timing, sticking, or bent valves.

- Check for VACUUM LEAKS inspect Intake manifold, gasket(s), and hoses.

- Check exhaust system for leaks, restriction, or damage.



FUEL SYSTEM MALFUNCTION - Check for lean Air-Fuel mixture, O2 Sensor, perform injector balance test, inspect regulator operation (check vacuum line and return hose), check fuel pressure

- Check fuel quality.