Circuit/System Verification
WARNING: This page is about a different car, the 2007 GMC Sierra, 2007 GMC Cab & Chassis Sierra, 2007 Chevrolet Silverado, and 2007 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
With the engine running at idle the Actual Fuel Pressure should be close to the Desired Fuel Rail Pressure. During engine cranking the Actual Fuel Pressure should be at least 10 MPa. Inspect the fuel return hoses and lines for external leaks or damage.