GM Service Manual Online
For 1990-2009 cars only

Cause

Correction

External oil leak

Inspect for any of the following conditions:

    â€¢ Restricted positive crankcase ventilation (PCV) valve
    â€¢ Restricted or kinked PCV hose or engine vent hose
    â€¢ Damaged, incorrect, or incorrectly installed PCV valve or hose
    â€¢ Excessive crankcase pressure

Rough Idle

Inspect for any of the following conditions:

    â€¢ Restricted PCV valve
    â€¢ Restricted or kinked PCV hose or engine vent hose
    â€¢ Leaking, damaged, PCV valve or hose
    â€¢ Vacuum hoses worn or not properly installed

Stalling or slow idle speed

Inspect for any of the following conditions:

    â€¢ Restricted PCV valve
    â€¢ Restricted or kinked PCV hose or engine vent hose
    â€¢ Leaking, damaged, PCV valve or hose

High idle speed

Inspect for a leaking, damaged, PCV valve or hose

Sludge in the engine

Inspect for any of the following conditions:

    â€¢ Restricted PCV valve
    â€¢ Restricted or kinked PCV hose or engine vent hose