2003 Silverado Rough Idle

[OchAyeZ71]

I have the 5.3 motor with about 38K on it.

 

I have reviewed several topics on this. My idle is slightly rough, enough to be noticable. I cleaned the TB with Sea Foam and it was black as coal as expected, mosly behind the vavle in the body. The idle seems a little better, but not perfect. I did not see any way to remove what I believe to be the Idle Air Control on the passenger side of the TB. There is an opening on the passenger side of the TB, which I also cleaned with a swab soaked with the SF. Posts mention removing torx screws to remove the IAC. I did not see any on mine. Did the design change with the '03 models? What exactly do you clean in the IAC.

 

Thanks for any feedback.

[chuckp]

I have the 5.3 motor with about 38K on it. 

 

I have reviewed several topics on this.  My idle is slightly rough, enough to be noticable.  I cleaned the TB with Sea Foam and it was black as coal as expected, mosly behind the vavle in the body.  The idle seems a little better, but not perfect.  I did not see any way to remove what I believe to be the Idle Air Control on the passenger side of the TB.  There is an opening on the passenger side of the TB, which I also cleaned with a swab soaked with the SF.  Posts mention removing torx screws to remove the IAC.  I did not see any on mine.  Did the design change with the '03 models?  What exactly do you clean in the IAC.

 

Thanks for any feedback.

 

<{POST_SNAPBACK}>

 

 

 

 

Sometime the intake gets warped and creates a vac leak..

 

chuck

[ProSport Tim]

Welcome to the fine world of the GM 5.3. Mine has done this since new. Dealer told me they ALL do it and theres' nothing to be done about it. Another 'great' stride for GM to re-invent and revert themselves back as the leading auto manufacturer.....christ.

[BRZ71]

I have an 03 with a rough idle I have been chasing for almost a year now. No solution as of yet. Let me know if you find something out.

[lahook]

could be the stock PCM tune

my truck idles smoother since the wait4meperformance tune

[ChevyTech007]

Take it to a dealer and have them check for update calibrations.

 

Subject: Idle Instability, Low or Rough Idle with Electronic Throttle Control (Clean Throttle Body) #04-06-04-040 - (06/14/2004)

 

 

 

Models: 2002-2003 Cadillac Escalade, Escalade EXT

 

2000-2003 Chevrolet Silverado, Suburban, Tahoe

 

2002-2003 Chevrolet Avalanche

 

2000-2003 GMC Sierra, Yukon, Yukon XL

 

2003 Hummer H2

 

with 4.8L, 5.3L or 6.0L V8 Engine (VINs V, T, Z, N, U - RPOs LR4, LM7, L59, LQ9, LQ4)

 

and Electronic Throttle Control

 

 

 

 

--------------------------------------------------------------------------------

 

Condition

Some owners may comment on an idle instability, low idle speed or rough idle.

 

Cause

Condition may be caused by deposits in the throttle body bore.

 

Correction

Clean throttle body bore and throttle valve plate of carbon using a shop rag and an appropriate cleaner. Refer to Engine Controls Repair Procedures - Throttle Body Cleaning Procedure. This procedure may be performed at any mileage necessary. Check to determine if the PCM calibration has been previously updated to one that includes the update for throttle body coking. For 2003 model year vehicles, look in the operating system portion of the calibration. For 2000-2002 model year vehicles, look in the engine portion of the calibration. If not, then update the PCM calibration to the latest calibration.

[chuckp]

I have the 5.3 motor with about 38K on it. 

 

I have reviewed several topics on this.  My idle is slightly rough, enough to be noticable.  I cleaned the TB with Sea Foam and it was black as coal as expected, mosly behind the vavle in the body.  The idle seems a little better, but not perfect.  I did not see any way to remove what I believe to be the Idle Air Control on the passenger side of the TB.  There is an opening on the passenger side of the TB, which I also cleaned with a swab soaked with the SF.  Posts mention removing torx screws to remove the IAC.  I did not see any on mine.  Did the design change with the '03 models?  What exactly do you clean in the IAC.

 

Thanks for any feedback.

 

<{POST_SNAPBACK}>

 

 

 

 

Take a propane torch without it lit and turnon and while the engine is running put it near where the intake seals against the heads and see if that makes it run smooth while running if it does you have a intake lead..

 

chuck

[OchAyeZ71]

Thanks for the feedback. I think I will try another clean or take it to the dealer since it is under warranty.

[michigan2500hd]

Be very careful cleaning the TB. The electronic units are very fragile. By manually moving the plate you can screw up the stepper motor that opens and close it. I did this to mine and after cleaning it i started it and it said "REDUCED ENGINE POWER" on the DIC. Had to replace the whole TB. It was done under warrenty but if you had to pay for it i'm sure it would be expensive.