Where is fuel pressure regulator located on 2004 cts

The fuel pressure regulator resides on the upper driver's side portion of the engine, directly below the plastic intake manifold shroud.

Here is a link to a video showing you exactly what you want to know...
fuel pressure regulator 2004 Yukon Denali


How To Install Replace Fuel Tank Pressure Sensor Suburban Yukon XL...

What engine does yours have ? 3.6 L engine the regulator is inside the fuel tank !
2.6 an 3.2L is on the fuel rail !
5.7L inside fuel tank !
The fuel pressure regulator attaches to the fuel return pipe on the fuel sender assembly. The fuel pressure regulator is a diaphragm-operated relief valve. A software bias compensates the injector on-time because the fuel pressure regulator is not referenced to manifold vacuum. The injector pulse width varies with the signal from the mass air flow (MAF)/intake air temperature (IAT) sensor.
With the engine running at idle, the system fuel pressure at the pressure test connection should be between 380-410 kPa (55-60 psi). With the system pressurized and the pump OFF the pressure should stabilize and hold. If the pressure regulator supplies a fuel pressure which is too low or too high, a driveability condition will result.
You would have to change The modular fuel pump sender assembly !
Now what makes you think you need to have it changed ?
Now

Where is the fuel pressure regulator located on my
2004 Cadillac CTS 3.6 L

fuel regulators are normally found on the fuel manifold and have a line going back to the tank of the inlet side of the pump

The fuel pressure regulator is located on the top of the fuel tank
Here is a picture.

Here's a link with a picture of it. SAVE 20 ON ONLINE SHIP TO HOME ORDERS OF 100 OR MORE Here's a new one. http://www.autozone.com/fuel-delivery/fuel-pressure-regulator/gp-sorensen-fuel-pressure-regulator/volkswagen/jetta/2004/4-cylinders-l-2-0l-sfi-sohc/80033_0_0

No that is not a low fuel pressure what you have is what million of other 2002 to 2004 explorer tract has the code is not low fuel pressure but a fuel pressure regulator located at the right top engine when this give false reading you will stall out at 1500 rpm especially when taking a turn it is a fuel pressure regulator code that has failed

Are you sure the fuelpump is good,even a bad regulator you should still have fuel preasure,the regulator if its not part of the pump should be on the fuel rail,

Hi. the fuel pressure sensor is part of the fuel pump assembly. You will have to remove the fuel pump to replace this. I would go ahead and replace the fuel pump while you are there.You will have to Pull the strainer off the fuel pump and discard it. remove the retaining clip for the fuel pressure regulator so that you can remove the fuel pressure regulator. Disconnect the electrical connections for the fuel pumps and the fuel level sensor. Remove the retaining clip for the fuel level sensor and remove the fuel level sensor by squeezing the locking tangs. the sensor is incorporated in this area.

Please rate and god bless.