Re: P0506 (Idle Control System RPM Lower Than Expected)
Actually, our engines don't have a lot of vacuum hoses. Check every connection on the air intake between the MAF sensor and the throttlebody. Spray some carb cleaner on each connection and see if the rpms change. If you still have the factory intake, check the plastic ducts and resonator for cracks. Don't forget to check the PCV hose from the top of the valve cover to the bottom of the resonator. Mine is showing signs of dry rot.
2005 Z71 LS Crew Cab 4X4 L52, 4L60E, GT4, Silver Birch Metallic
Waiting for the Baby Duramax.
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