04 4.8 fuel pressure regulator

[Scott Mclay]

I have a new to me 2004 Chevy Silverado work truck I cannot find the fuel pressure regulator on the fuel rail anywhere is there anywhere else I might find it

[CamGTP]

There isn't one. The returnless fuel system as the regulator built into the fuel pump.

[Scott Mclay]

Thanks i just bought this as a work truck and it idles very  rough and looking for answers.  Has new fuel pump and plugs seems ok above idle just a work truck but would like to get it a little smoother has a 0171 code

[redvett]

Looks like you have a vacuum leak at the plenum to cyl. head. https://www.yourmechanic.com/article/p0171-obd-ii-trouble-code-system-too-lean-bank-1-by-andrew-quinn

[Scott Mclay]

Thanks ive heard thats common my 09 was spot on before i bought my new 17 thanks how hard of a job is that i used to be a mechanic 20 years ago

[Scott Mclay]

I live in mass and it was cold this morning and it idled better than usual does that help at all

[CamGTP]

No not really.

 

Investigate the lean code. Could be anything from the intake gasket leak to an exhaust leak on the exhaust manifolds before the o2 sensor.

 

Intake gaskets are easy, (to me anyway) there are tons of video's on youtube about how to replace them. You can clean the throttle body and MAF sensor with the proper cleaners while your at it too.

[redvett]

Might  want to look at your knock sensors too.

[Scott Mclay]

No exhaust leaks clean maf and throttle body i dont expect a perfect truck for 185000 miles. Knock sensors would not cause this condition at idle would they

. Thanks again

[redvett]

Intake leaks will set 0171 code. Doing the knock sensors while your in there will save you time and money.

[Scott Mclay]

Ok got you thanks

[redvett]

BTW I f the KS are looking bad get the pigtail and lookup on youtube the GM recommended fix with silicone.

[Scott Mclay]

Yes i have heard of making the little dam out of silicone, i appreciate it it but dont know if i should just change intake gaskets or take it to mechanic 

[Scott Mclay]

The only hard part is the fuel line rite, i have the tool and the 10 or 12 bolts and unplug a few things 

[davester]

All the bolts are present in both exhaust manifolds?  It's common for the bolts to break off over time, and the exhaust can actually suck clean air in, which makes the O2 sensors read lean...