Rough Idle

[JeRzEy SiLvErAdO]

Hey guys how are ya, I have a 2002 5.3 with 53k miles and over the past 6 months or so I've noticed that the truck doesnt idle like is used to either in drive or in gear.. About 200 miles ago I had the fuel pump/sender changed along with the fuel filter just for the fact I wanna get my $$$'s worth for my extended warranty and my dad is a tech at the dealer... and I also cleaned my air filter but nothing changed. I usually put in fuel injection cleaner about every 6 months and my fuel filter gets changed every 10k ish... I have never touched the wires or plugs but I thought they are good for 100k.. The truck runs fine, am I being anal or is there somthing wrong??? O and I am not getting any codes either.Thanks guys

[MT-2500]

Get it put on a good engine capable scanner and see what shows up.
One thing to watch is gas in the vacuum line on the fuel pressure regulator.
MT

[east302]

Try a throttle body cleaning, seems to help whenever mine starts to stumble at idle.

[JeRzEy SiLvErAdO]

[quote=MT-2500]Get it put on a good engine capable scanner and see what shows up.

I put it on a scanner and nothing shows up??

[JeRzEy SiLvErAdO]

Originally Posted by east302

Try a throttle body cleaning, seems to help whenever mine starts to stumble at idle.

Hmm... I give that a shot, i havent cleaned the throttle body since I put on my cold air intake 3 years ago.... U might be on to somthing

[masapell]

Originally Posted by JeRzEy

SiLvErAdO I put it on a scanner and nothing shows up??

MT-2500,

Will fuel bypassing into the vacuum line show up on a scanner when the fuel pressure regulator is not completely faulty? I have an idle that shakes a little and have never been able to correct it. Would a new regulator help that situation? I, like many others, have changed the spark plugs/wires and run fuel cleaners through to no avail. Any ideas would be greatly appreciated.


Sincerely,
Matt

[MT-2500]

[quote=JeRzEy SiLvErAdO]

Originally Posted by MT-2500

Get it put on a good engine capable scanner and see what shows up.

I put it on a scanner and nothing shows up??

Did you check all sensor and data readings?
Past or present or history codes and miss fires?
On clean the air filter are you running a K&N or after market air filter?

[sc_customs]

just cam ur truck and then rough idle will be cool

[WalrusInc]

100k on a tune up is the worst thing that anyone ever told a customer. People are already piss poor at maintenance without telling em they won't have to do a tune up as long as they own the car. Clown shoes. And red noses.

[TexasF355F1]

Is the idle just rough, or does the truck sort of lurch if you remove your foot from the brake. As well as a shakey take off?

My truck did that and the culprit was the pressure regulator.

[JeRzEy SiLvErAdO]

Originally Posted by sc_customs

just cam ur truck and then rough idle will be cool

I have a TR cam sitting in the box waiting to be installed as well as a transgo HD shift kit,trans cooler and a vette servo.... Im waiting till august to install them... Just incase somthing serious breaks on my truck before the extended warranty is up... I am still up in the air about whose tuned PCM i should get

[JeRzEy SiLvErAdO]

Originally Posted by TexasF355F1

Is the idle just rough, or does the truck sort of lurch if you remove your foot from the brake. As well as a shakey take off?

My truck did that and the culprit was the pressure regulator.

Just a rough idle, The pressure regulator was just changed 250 miles ago... I just cleaned the throttle body and MAS and put some GM Fuel Injection cleaner it seems to be good now... What do u think about changing the plugs/wires..... There is a speed shop within a hour of my house that takes out the injectors and cleans them with some sort of sonic cleaning.... any of you guys heard of this or tried this...

[WalrusInc]

We use a Snap On Motorvac machine that interrupts the fuel system on the vehicle and feeds off a tank on the machine. It uses a cleaning solution mixed with fuel in the tank and works damn good. Most vehicles show immediate improvement in both idle and high rpm running capability. It may be cheaper than the sonic cleaning, but either way, I'd look into it.

[JeRzEy SiLvErAdO]

Originally Posted by MT-2500

Get it put on a good engine capable scanner and see what shows up.
One thing to watch is gas in the vacuum line on the fuel pressure regulator.
MT

Son of a Bitch,I checked for codes with my interceptor gauge today, just for shits and giggles because I kind of beat on my truck drivein down the shore for the weekend and I had P0171 & P0171 codes come up.. I know what it means, I had the intake gasket changed as well as had the system checked for a vac leak when the code came up 6-8months ago and like I said before I had the pressure regulator, pump and fuel filter changed and well as cleaning my dry airfilter 350 miles ago.. The check engine light never came on and the truck still runs smoooth.. any ideas???

[MT-2500]

That is where you need a good engine capable scanner.
A lot of good info in there.
Check history frames and get the fail frame of when it set the codes.
Not sure but if your fuel system and pressure checks out you may have some dirty injectors.
Again a engine capable scanner will run a injector balance test.
Good Luck
MT