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 ACTION


Electrical misfires Check ignition system



Vacuum leak Check vacuum lines and routing in
"Vacuum and Vapor Hose Routing"
in Emissions - Check intake manifold
and vacuum components



PCV malfunction Check PCV system in "Testing
Procedures" in Emissions



Initial timing incorrect Check Ignition Timing in "Adjustment
Procedures" in Emissions



Incorrect Spark Advance Check Spark Controls in
"Fuel Injection and Computerized Engine Controls"