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.