Help understanding fuel pressure whats correct?

invalid@example.com (method0075), method0075
Tue, 18 Nov 2008 01:37:05 +0000

E34 1992 535i M30

Ok so I hooked up a pressure gauge to my fuel line today.

I got with vacum line looked up to FPR...
39 PSI @ idle

I got with vacum line disconnected from idle...
Approx. 53 PSI @ idle

With vacum line hooked up and car in park, I give it gas/rev it up and it goes up to
53 PSI holds till I let off gas and goes back down to 39 PSI

So can someone tell me if this seems wrong. I did some research I thought with more vacum applied, such as when I rev the motor or the...

Help understanding fuel pressure whats correct?