I have one with (P/M), *& another one with Vacuum (I "converted" to Vacuum) ... BOTH are great ! (It seems once I change the "dreaded dark fluid", that I run into all the problems !) ... SO: on the other car I left it alone, took it back to the Dealer for a new Pressure Switch (there was a recall), and I've enjoyed perfect operation since.
It amazed me that they found a Switch even ! (But I used top work there).
Want a wake - up call ? (*Maybe this happened with you ?) *Have one (a "power-master") go "OUT" when you least expect it ! Trust me; You'll won't soon forget when it does !