Check for Vacuum Leaks First!

Vacuum leaks present symptoms similar to a faulty MAF Sensor. When replacing the MAF, always check for vacuum leaks, too. Common sources include:

• Cracked or loose Vacuum Hoses / Connectors - an audio Stethoscope can help detect air induced sounds from vacuum leaks.
• Leaking Intake Manifold Gasket (found in the "Engine" category) - Vacuum Gauge readings below 17-22 in-Hg (normal manifold vacuum at sea level) at idle may indicate an intake manifold gasket leak.
• Note: As elevation increases, readings decrease. Subtract 1 in-Hg from normal manifold vacuum reference for every 1,000 feet increase in elevation above 2,000 feet.
• Stuck open PCV Valve - remove the PCV Valve and gently shake it; if it does not rattle, the valve is clogged or dirty and should be replaced.
• Cracked Intake Boot (found in the "Engine" category)

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