I have a 2003 GMC sonoma 2 wheel drive 4.3 v6. I just got a fuel pressure gauge and when I turn the ignition on the gauge reads 60 psi so I think my fuel pump is good. Now I am trying to figure out if it's a crank or camshaft sensor or the fuel pressure regulator but I don't know where they are located. Does anyone know where they are located? Also I have a meter to test the sensors but what setting do you put the meter on to test it?

Mine did the same thing a while ago and turned out to be a bad fuse block. Sometimes it crank and sometimes not. I just replaced the fuse block and all was good.
Fuel injectors located at the end of the fuel rail at the front of the engine.