High HC & CO - at High RPM

Condition: High Carbon Monoxide and Hydrocarbons during cruise (2500 rpm).


POSSIBLE CAUSE ACTION


Electrical misfires Check ignition system.
SEE IGNITION SYSTEM/ OSCILLOSCOPE PATTERNS.

Initial timing incorrect Check base timing.
SEE IGNITION SYSTEM/ ADJUSTMENT PROCEDURES.

Check cam timing.

Incorrect Spark Advance Check Spark Controls.
SEE IGNITION SYSTEM/ TIMING SPECIFICATIONS

Vacuum leak Check vacuum lines and routing.
Refer to Vehicle Emission Control Information (VECI) label under hood.

Check intake manifold
and vacuum components

Faulty canister purge system Check Fuel Evaporative System.
Evaporative Emissions System

Restricted exhaust Check Catalytic Converter.
See Plugged or Restricted Exhaust Testing.

EGR malfunction Check EGR system.
Exhaust Gas Recirculation

[1][2]PCV malfunction Check PCV system.


Fuel Injection malfunction Check fuel pressure.
Perform injector balance test.
Service Fuel Injectors (Pressure cleaner).