: 2005 sts help

09-17-10, 05:54 PM
I have 05 sts with 80K miles on it, I don't even know where to begin about all the problems I've had with it, but to cut the long story short I am looking for some help on Checking the FUEL PRESSURE and Fuel Pressure Regulator, I need help locating Fuel Pressure Regulator and where is the fuel pressure valve so I can check the fuel pressure.

2005 sts 4.8L V8 N*.

The problems I have with the car are "Engine Power Reduced" and TC.
The car would shut off while driving, it would hard shift and computer would display Engine power reduced and TC light would come on, Almost always it starts right back up, and than sometimes it just would shake when trying to turn it on. I have taken it to a dealer and replaced O2 sensors, MAF sensor, re-programed the computer in it. I cleaned the Throttle body, tightened down the air manifold, changed the spark plugs in it.

Now the only thing i can think of is, it's either not getting enough fuel or the Fuel Pressure Regulator is bad.




09-18-10, 04:51 PM
Have you had it diagnosed by a Caddy expert with a Tech II?

09-18-10, 11:53 PM
I would try to unplug the wheel sensors in the back and see if that makes a difference. I think engine power would be reduced and traction control active if the car thought the rear wheels were spinning while the front ones are stationary.


09-19-10, 01:32 AM
Well I think I have some good news, I was looking over the engine and I found out that the air transfer hose was broken on back of the air intake manifold. I took the fuel injectors off and air manifold, went out and bought some hose that fits right over the pipe, as the old connectors were unusable, and just fixed it with some clamps. Turns out that was the problem, engine is back to normal idle, no choking and/or shutting off. For all other STS owners, when you have some time, make sure that you check this, as these are really easy to brake off, because of the heat from the engine the connectors harden and break just by slight movement, just reach back behind the air manifold put a finger over and listen for air coming out, of course the engine has to be running. If it is leaking air once you put finger over it, engine sound will change.

I also checked fuel pressure and checked to see if air pressure regulator was throwing any fuel out, turnes out that was all good.

Keeping my fingers crossed as to see if anything else turns up. As of now engine is running smooth as it was when i bought it, engine performance has also improved quiet a bit.

If anyone is wondering, this air transfer pipe is on the left side of the engine block. looking over the engine from front of the car. Its same hose as the one going off of air intake pipe. It comes off of there and goes back behind the air intake manifold. If it's broken and you need help/instructions on how to get to it, just ask and i will do a write up.