Here's another dumb newbie question. When you set an adjustable fuel pressure regulator, its supposed to be set to 45psi (talking stock here)with the vacuum off, but is that with the engine running or with the engine off, and key turned on (so you have pressurized fuel lines). I just don't want to muck anything up. Thanks
It's easiest to do it with the car running, since the pump is running continuously to maintain pressure.
If you have a switch to run the fuel pump, then you can just switch the pump on.