What is the easiest way to check the fuel pressure in our cars? I am having a small fuel issue and I am trying to isolate it to pump or regulator because everything else has tested fine. Thanks

Easiest way is to connect a pressure gauge to the fuel line between the filter and the regulator.

As far as it testing your pump, really you need to check flow to check the pump...
If the pump is flowing almost nothing or nothing, it will show, but if it's weak, the regulator will still hold pressure.