98 Z71 Hard to start when warm-wheres the fuel pressure regulator?

98 GMC SIERRA 350Vortec, 107K, starts great when cold, or after a few minutes of shutting down, but turns over several times before starting when hot and sitting for 30 min or more, anyway was told possible fuel pressure regulator, bought one at dlr, but cannot find it to replace it, not like the new 5.3 or 4.8...Runs great otherwise.

Regulator is located on the injector body under the upper intake.