Operation CHARM: Car repair manuals for everyone.

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 Inspect vacuum hoses for
proper routing and damaged lines
Check intake manifold gasket area



PCV malfunction Check PCV system



EGR malfunction Check EGR system



Incorrect spark advance Refer to computerized spark control



Verify vehicle is operating in Refer to ON-BOARD DIAGNOSTICS
Closed Loop at steady throttle
(2500rpm) and oxygen sensor is
working