High HC -- at High RPM

This condition is indicated by abnormally high hydrocarbon emissions with low or normal carbon monoxide emissions during cruise (2500 rpm).

POSSIBLE CAUSE
Electrical misfires.

ACTION
Check ignition system.



POSSIBLE CAUSE
Vacuum leak.

ACTION
Check vacuum lines and routings.
Check intake manifold and vacuum components.



POSSIBLE CAUSE
PCV malfunction.

ACTION
Check PCV system. Positive Crankcase Ventilation



POSSIBLE CAUSE
Initial timing incorrect.

ACTION
Check Ignition Timing.



POSSIBLE CAUSE
Incorrect Spark Advance.

ACTION
Check Spark Controls.