No need to look into it, you want it pegged at anything above idle. Sounds like your pressur eis fine. It can dip as low as 10psi or so at hot idle in the summer (possibly lower) and should peg as soon as the revs come up. Anything less than pegged - 45psi/3 BAR - when above 1K RPM could indicate an internal problem.
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72
'02 CLK320 Cabriolet - wifey's mid-life crisis
2012 VW Jetta Sportwagon TDI...at least its a diesel
Non illegitemae carborundum.