Strange rought idle but only sometimes

[Glock Guru]

Well I now have about 15k on my 06' and so far so good. Over all I have been very happy with the truck. had to get the passenger side electric mirror replaced (would not move up and down) and a gasket on a roof light that leaked, buts thats all.



The problem is this: every now a then the truck will idle rough after starting it. It only seems to happen after the truck has been running during the day. It has never happen when I start it in the morning. If the rough idle starts, it will last for say, 10-20 min. or if I drove the truck and made another stop and let the truck sit it mite go away. No set time place or pattern.



Any idea??

 

[Kry226]

My 04 does the same thing on occasion. It does drive me crazy, but it goes away quickly and I always forget about it before it pops up again. Have you changed/checked your fuel filter?

 

[bagd99dak]

my 05 does that somtimes. has done that since it was new and now has almost 26k on it. no problems. im just gonna say its a diesel thing and im not worried about it. lets you know you have a manly motor under the hood. haha

 

[Glock Guru]

Could the rough idle be the precursor to some kind of injector failure or something with the lift pump?



-Troy

 

[Glock Guru]

Come on, someone must have heard about this at the dodge dealer by now.



-Troy

 

[cerberusiam]

I have heard that is one of the symptoms of a failing injector. However, reproducing it and getting a competent tech to run the tests and find a problem and getting STAR to approve a fix is a long battle.



Definitely seems the outright failures are decreasing but the intermittent problems with idle and mileage still exist. How are you using the truck? Daily commuter or working it? Best advice so far is run additives, a strong dose of cleaner periodically, work it hard, and see if that helps.

 

[CDyksman]

Glock Guru, I have come to figure out that my '06 idles rough only when I don't have the trailer on, which seems to curb the vibrations.

 

[DBryson]

I have read that there is a TSB on this somewhere.

 

[Schrowang]

One of the things that I've noticed is that the harder you work the Cummins, the smoother it runs. About 50% of my driving is local and I use Power Service additive every third tankful. So after a month or so of this, I'll get a long trip either towing or not, but I run extra additive during the first tank of the trip and really open her up. By the end of the trip, 2,000 miles or so, the Cummins has smoothed right out.



My Dad was a road service tech and finally the Service Development Manager for the local Cat dealer in NJ (42 years). He always said that the longer a diesel runs and the harder it works the better. Oo. He's fixin' the Lord's fleet of earthmovers now.

 

[Deleted member 995608]

My 04. 5 did that exact same thing for a while. Finally the truck quit on me going down the road. Turned out to be the lift pump.

 

[Glock Guru]

The truck is mostly a daily driver with no hard work. I use Power Service or Lucas on each or at min. every other tank. You guys are bumming me out with the lift pump / injector stories. I have somw FEMA work comming up pulling trailers soon. I guess I cound use the CTD rather than my 01' Power Joke (its an XL work truck). I guess I will call my dealer and try to get some info on the TSB if there is one.



-Troy

 

[Tryingit]

Its normal. During cold weather right after starting it will run rough for around 5-7 seconds then even out. There were numerous threads here and else where on this. . Almost everyone on this threads experienced the same systoms. I never have the problem in warmer weather. My lift pump is fine according to my gauge. There was TSB on the earlier trucks like mine. It was a computer recalibration, didn't help much. I even bought my to the dealer and they spents some time checking the injectors at my request. Unless they were BS (NO Never) they said it aids in warming up the truck. Nothing has gone bad in the past two years, knocking on a piece of wood right now.

 

[BMH95]

I drove mine to Vail and back a couple of weeks ago (Chicago), and it did something similar to me. I was hammmering on it at 80mph, empty, for 10 hours straight on the way home. This was after doing 80 the whole way to Vail, and beating it in the mountains for 2 weeks. I figured rolling 39000 miles during the trip would make sure it was good and broken in. Well, I stopped to fill her up in Iowa, and it was sitting there shaking at the ramp stop light. It shook the whole time I filled it up (even the new bride noticed it was idling rough), but was smooth once under accelleration and cruising (at 80 again). When I got home, it was rough idling again. The next morning, it was fine, and it hasn't done it since. I normally drive around home at 64mph on the highway, and it get 20ish there. It got between 16. 6 and 17 mpg at 80. So in the last week, it hasn't run rough once. I'm as confused as this guy, and it sounds like a similar gremlin??

 

[Tryingit]

Sorry I misread the post. Mine has done that twice. Just ran rough for a little while, not during a cold morning start.

 

[Glock Guru]

Mine has done it in warm weather so far. we have not had a cold spell yet this far south. It seems to do it mid day depending on h0w many start and stops I make and how many times turn off and crank the motor. I second it's driving great, then stop at the bank, cut the engine. I go in the bank for 3-5 min. , come out and start the truck and BAM! rough idle. I don't want it to sound like it happens all the time, because it does not. But it does not seem to have any set patern to it other than later in the day with the motor fully warm.



-Troy

 

[BRandolph]

Take it out and tow a large trailer with and run the crap out of it. That will most likely get rid of the miss. I have been seeing more of this at the dealer I work at. The injectors get carboned up and start missing at idle. Seen one yestrerday. Another tech was working on it. It had 30000 miles and was missing at idle on #6. He called STAR to get an injector. They requested the idle time and percent at idle. He was told that the customer had to try some cleaner first and use his high idle is idling for a extended time. We have a BG diesel injector clean service the tech did that on the truck I cleared the idle up and made it run better. If you can find a place that has the BG injector service try it. I did it on my truck and it picked up a good amount of power.

 

[DGamelin]

My truck serges after I've been towing hard for quite a few miles. When I roll up to a stop sign and stop it serges up and down. It runs smooth but serges.



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

04. 5 3500 6x6 quad cab 6 speed 373 27k

93 250 2x4 xcab auto 342 240k

 

[Diesel Power]

from 80* to 102* my truck will missfire on one cylinder and you can feel and hear it out of the exhaust i think it is the rail pressure sensor or currupt ecm info. but after 102* it clears right up, any thoughts

 

[TCDiesel]

Missed communication between CMP and CKP. the ECM will use both sensors on start up ,once up and running the ECM will used the CMP as Backup to the CKP,The CKP is the Primary Engine speed sensor,although the CMP is always sending a signal to the ECM. It is in this area that down-loaders will screw up the Process. So when using them and switching power Levels make SURE truck is warm and running at several minutes BEFORE switching Levels

 

[JWaugh]

i have 15k on my 06 as well and intermitently it starts with a really rough idle. the last time it did this i left it running to see if it would clear up or set a code but it did not. i then checked the individual cylinder temps and found that #6 cylinder was not working and #3 was cooler than the rest but about 100'f cooler than the rest. has any one else done any checking of their exhaust temps?. when it ddoes start rough if you shut it off and restart it sometimes goes away and other times it does not. wondering if it could be a timing sensor or something. thought maybe fuel pressure but why only these two cylinders. also it seems funny that it is 2 cylinders in a row in the firing order ???? anyone have any thoughts???