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Home >> GMC >> 1991 >> Forward Control 5.7 K, Standard, NV4500/MT8 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System/Component Tests >> Emission Systems & Sub-Systems (Gasoline) >> PCV >> Required Service
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Required Service

The PCV system may require service for obstructions if any of the following conditions exist:

A PCV leaking valve or hose could cause:

If engine idles roughly, check for clogged PCV valve and for plugged or broken hoses BEFORE adjusting idle. Check correct PCV valve application to ensure the correct valve is fitted. Replace PCV valve if required.