Not starting

Thank you.

What do you believe is the tell tale sign of the regulator? Are you leaving the fuel pressure tester on it while you are driving?

Roy

From what I have read the signs of a faulty fuel pressure regulator are rough idling, poor acceleration response, backfiring, black exhaust smoke, and unusual exhaust odor.

From GMCTruckClub.com
Fuel Pressure Regulator Failure Symptoms:
Engine runs rough
Engine stumbles or sputters
Engine runs very rich - black smoke from the exhaust
Engine will not start
Engine starts but stalls shortly after startup
Noisy fuel pump
Noticeable decrease in fuel mileage

No, I have not tried driving with the tester on, I am not even sure that I could without removing the hood because of the hose.

You would need a longer hose.

A lot of those symptoms can come from other components not just the regulator.

Roy