Trailer Life Magazine Open Roads Forum: Tow Vehicles: Rough Idle
Open Roads Forum Already a member? Login here.   If not, Register Today!  |  Help

Newest  |  Active  |  Popular  |  RVing FAQ Forum Rules  |  Forum Posting Help and Support  |  Contact  

Search:   Advanced Search

Search only in Tow Vehicles

Open Roads Forum  >  Tow Vehicles

 > Rough Idle

Reply to Topic  |  Subscribe  |  Print Topic  |  Post New Topic  | 
Page of 2  
Next
Sponsored By:
Thunderbolt

North Branch, Mn USA

Senior Member

Joined: 07/03/2003

View Profile


Offline
Posted: 02/07/18 07:44am Link  |  Quote  |  Print  |  Notify Moderator

I have a new issue will my 03 Chevy 6.0. When the truck is cold it idles rough. Doesn't actually feel like a misfiring cylinder. In gear at a stop light the idle will drop below 500 rpm and the engine stumbles and then the idle jumps up to about 1,000 rpm and then back to normal for a moment and then it repeats. Once it was up to operating temp it idled fine. Since it only did it when cold most of my research showed tat the intake manifold gasket was the likey the problem.
Now this morning the temp outide was -6 degrees and the truck ran rough until it was warm and then it was fine as usually. Then 25 miles down the road I run into traffic and had to stop and the truck did the same rough idle as it was doing when it was cold. It did it about 5 or 6 times and then idled fine again. Warm or cold it runs fine once you are off of idle. Looking for some input.


Bryan
2003 2500HD Ext. cab short box
6.0 liter 4.10 gears, Nelson performance PCM
98 K1500 4x4 heavy duty 1/2 ton
6,600lb GVWR 5,280lbs on the scale empty
14 bolt rear diff. 3:73 , Tranny and oil coolers
371,000 miles still purrin' like a kitten

enblethen

Moses Lake, WA

Senior Member

Joined: 01/05/2005

View Profile






Posted: 02/07/18 07:50am Link  |  Quote  |  Print  |  Notify Moderator

Sounds like a vacuum leak. Some vehicles have a thermal control vacuum sensor. Go over the vacuum line diagram under the hood. Look for a thermal valve.


Bud
USAF Retired
Pace Arrow

2003 Chev Ice Road Tracker


Thunderbolt

North Branch, Mn USA

Senior Member

Joined: 07/03/2003

View Profile


Offline
Posted: 02/07/18 08:06am Link  |  Quote  |  Print  |  Notify Moderator

enblethen wrote:

Sounds like a vacuum leak. Some vehicles have a thermal control vacuum sensor. Go over the vacuum line diagram under the hood. Look for a thermal valve.


I am going to check it out more after work. It appears that the intake manifold gasket is a very common problem with these trucks as well. Usually the vaccum leak goes away once they are warm though unless mine is really bad ?

LIKE2BUILD

Decatur

Senior Member

Joined: 09/30/2004

View Profile



Good Sam RV Club Member

Offline
Posted: 02/07/18 08:55am Link  |  Quote  |  Print  |  Notify Moderator

Remove the idle air control valve and thoroughly clean it and the cavity. A sticky valve with respond to the ECM properly but not physically move. So, you can get odd idle behavior like you saw but never trip a check engine light.

My FIL had a chevy van that was racing at idle. He could go 45MPH and never press the throttle and had no check engine lights. I replaced the AIC and all was good.

KJ


2012 Sandpiper 32QBBS
'14 Ram 2500 | Crew Cab Long Bed| 4X4 | Cummins TurboDiesel
Curt Q20 with Ram 5th Wheel Prep
2000 Crownline 205BR
1997 Ranger Comanche 461VS
'96 Polaris SLT780 PWC
'94 Polaris SLT750 PWC
3 Wonderful Sons (18, 11, & 10)
1 forgiving wife!!!


troubledwaters

Potomac

Senior Member

Joined: 02/17/2017

View Profile


Online
Posted: 02/07/18 09:36am Link  |  Quote  |  Print  |  Notify Moderator

Don't know much about Chevy but it sounds like an ignition coil problem to me. Is this a Coil Over Plug (COP) design? Get a code reader and find out which cylinder has the most misfires. It probably will be like 10 times more misfires then the next closest one, this is a good indication it is the COP (or it could be the plug but less likely).

NJRVer

NJ

Senior Member

Joined: 05/16/2011

View Profile



Good Sam RV Club Member

Offline
Posted: 02/07/18 10:25am Link  |  Quote  |  Print  |  Notify Moderator

I received a letter from GM on my '09 6.0 about rough idle quite a few years ago.
If my mileage was still under 100,000 and the rough idle happened the letter said to bring it to the dealer.
Of course I had over 100,000 on my truck by the time I got the letter.

Thunderbolt

North Branch, Mn USA

Senior Member

Joined: 07/03/2003

View Profile


Offline
Posted: 02/07/18 01:34pm Link  |  Quote  |  Print  |  Notify Moderator

LIKE2BUILD wrote:

Remove the idle air control valve and thoroughly clean it and the cavity. A sticky valve with respond to the ECM properly but not physically move. So, you can get odd idle behavior like you saw but never trip a check engine light.

My FIL had a chevy van that was racing at idle. He could go 45MPH and never press the throttle and had no check engine lights. I replaced the AIC and all was good.

KJ


I don't think the 03 and newer actually have an removable IAC like the older ones did.

Jay Pat

Round Rock, TX

Senior Member

Joined: 06/03/2009

View Profile



Good Sam RV Club Member


Posted: 02/07/18 01:41pm Link  |  Quote  |  Print  |  Notify Moderator

From what I've read, it could be sticktion(?)with one of the injectors.
Arches diesel treatment has been known to eliminate sticktion.
If you can't find it on the shelf at auto parts, I would try any diesel treatment.
Pat


2010 Ford F-350 SRW
2011 Keystone, Sprinter 310


kw/00

Florida

Senior Member

Joined: 05/13/2004

View Profile



Good Sam RV Club Member


Posted: 02/07/18 03:19pm Link  |  Quote  |  Print  |  Notify Moderator

I had my old one do the same. Intake manifold gaskets were leaking. After I fixed that issue I had the Cpk go out.... that was a easy fix as well! That 6.0 is so built proof that I bought an 09.. my old one had over 200k. So that's my take on it, replace the gaskets with the newer updated ones. Good luck and keep us posted.


A truck, a camper, a few toys, but most importantly a wonderful family.

Thunderbolt

North Branch, Mn USA

Senior Member

Joined: 07/03/2003

View Profile


Offline
Posted: 02/07/18 04:12pm Link  |  Quote  |  Print  |  Notify Moderator

kw/00 wrote:

I had my old one do the same. Intake manifold gaskets were leaking. After I fixed that issue I had the Cpk go out.... that was a easy fix as well! That 6.0 is so built proof that I bought an 09.. my old one had over 200k. So that's my take on it, replace the gaskets with the newer updated ones. Good luck and keep us posted.


I am thinking intake gaskets too from what I am reading. Looks pretty easy to do as well compared to my 5.7 Vortec.

Reply to Topic  |  Subscribe  |  Print Topic  |  Post New Topic  | 
Page of 2  
Next

Open Roads Forum  >  Tow Vehicles

 > Rough Idle
Search:   Advanced Search

Search only in Tow Vehicles


New posts No new posts
Closed, new posts Closed, no new posts
Moved, new posts Moved, no new posts

Adjust text size:

© 2018 CWI, Inc. © 2018 Good Sam Enterprises, LLC. All Rights Reserved. | Terms of Use | PRIVACY POLICY | YOUR PRIVACY RIGHTS