Fuel Pressure At Idle
WARNING: This page is about a different car, the 2002 Mercedes-Benz G500. However, it is still accessible from the selected car via links, so may be relevant.
With engine off, connect fuel pressure testing equipment. Start engine and idle. Fuel pressure should be 54-61 psi (3.7-4.2 bar). If fuel pressure is within specification, test is complete. If fuel pressure is not within specification, possible causes are fuel pump malfunction or faulty fuel pressure regulator. Check fuel pump for proper operation. See FUEL PUMP TESTS . If fuel pump is okay, replace fuel pressure regulator.