Fuel Pressure? 2006 ML350 272 engine

[johnflight1]

I tried looking in wis but could not find it.Would any one know what the fuel pressure should be on a ML350 272 eng 2006. I know the old ML320's were 55 to 60 psi,but I could not find anything on the Ml 350.
Also should it hold pressure for a certain amount of time when not running?
Thanx in advance John......................................