For 1990-2009 cars

Symptom | Correction
--- | ---
External oil leak | Inspect for any of the following conditions:

• | Restricted or kinked PCV hose or engine vent hose

• | Damaged, incorrect, or incorrectly installed PCV hose

• | Excessive crankcase pressure

Rough Idle | Inspect for any of the following conditions:

• | Restricted or kinked PCV hose or engine vent hose

• | Leaking (damaged) PCV hose

• | Vacuum hoses worn or not properly installed

Stalling or slow idle speed | Inspect for any of the following conditions:

• | Restricted or kinked engine vent hose

• | Leaking (damaged) PCV hose

High idle speed | Inspect for a leaking (damaged) PCV hose
Sludge in the engine | Inspect for restricted or kinked PCV hose or engine vent hose