We have an older (2005-ish) pump that with the tester, struggles to get 155.
This was with a battery charged up fully, the gain knob at 8, and the initial at about the 1-2 o'clock.
Is this "normal"? I also notice a lot of oscillation on the needle at full pressure, it swings from around 130 to 155 rapidly.
Car seems to perform ok, no knock or any apparent failures in the system, but I'd like to be proactive on the pump rather than reactive if this sounds like the pump is falling down...