Fuel pressure what should it be

[mnthny4]

Good day to all Audi techs ,I'm working on a 2006 s4 4.2L v8 need some help here from anybody who has a good running s4 with correct fuel pressure when first turning key on eng off also please tell if u have pressure at line when u first pull line from car sitting overnight ,then what's the fuel pressure reading at idle is it over 3.5 bar -3.8bar ,this is what I got from car I'm working on from overnight I pull fuel rail line no pressure fuel just drip very slightly connect fuel gauge turn key on,engine off reading was about 2.5 bar after a minute or more fuel pressure drop to near 2.0 bar pressure ,started car let idle pressure went up to 3.8bar near 4bar steady rev engine pressure drop to about 3.6bar then back to 3.8 there about ,can someone please post there pressure readings from a known good running s4 with the fuel rail that does not carry the pressure regulator built onto it hence the pressure regulator is a part of the fuel filter assemble please please someone post this info for the s4 4.2L community here ,any help would surely be appreciated thanks,one more side note this car does not carry a vacuum line to pull from a pressure regulator so all data info don't apply here thanks again for any help.