I need some advise, I have a small trucking company which I run a 3500 06 Dodge Quad cab. I run it pretty much like you do a big rig, it pulls a 38' gooseneck and I can legally gross a total weight of 29500lbs.I basically live in the truck when I am on the road which means it idles alot.

Ever since I got the truck in feb it's always gotten poor fuel mileage. I had hoped it would improve as it got more miles but that hasn't been the case, I average around 8 mpg. However, from what I have been hearing from other 06 owners theres hasn't been much better.

Anyway, now that the hx is outta of the way. About month ago I noticed it was idling a little rough so I tosed a bottle of gray diesel kleen through a couple of tanks. Since I usually go through around 400 gallons of fuel a week, I usually run some clearner through it. It seems to have helped a little but now it's back to it's rough idling, I have also noticed soot on the ground under the tail pipe. ( I have a down pipe) As to highway performance there has been no change, its strong with a load, hills don't bother it much and powers up esp after 2k, nicely. I do notice it is smoking some but nothing major considering the loads I put on it. I have also noticed that the rough idling isn't consistent, sometimes it's smooth as glass other times it's really rough. HELP, what could be causing the problem?

Thanks Tad
Clearshot Trucking

 

how many of these hard miles have you put on the rig? dusty dry conditions? maybe one tank of poor fuel along the way? Have you opened up the stock air intake system at all to let er breathe a little easier? how bout a fuel filter change? As the motor breaks in it starts to get a little looser and starts a bit more of a familiar diesel rattle, Since you tow heavy just as a side note I hope you checked the air in the tires before ya started loading it, I think they send em to the lot with 40 psi so they ride nice and soft for their test drives.......

EDIT: O by the way, welcome to the site.
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Assuming that all the fluids and filters are in check maybe you have a bad injector.
Will

 

The excessive idling is making it run rough. For some reason the 06's are more prone to it than the previous years. The tech explained it to me as carbon buildup on the injectors when it idles from the 3rd injection pulse not buring right. The way to get rid of it is raise EGT's up into 1300+ to burn off the carbon buildup.

Fuel milage?? Hit or miss. Some guys are claiming 18+ unloaded... I get 14.

 

you need to get a 2 micron fuel fitler or you will lose injectors because i have had this happen to me twice before i was told to run that fuel filter you are getting bad fuel and it is slowly killing your injectors. as far as mileage mine get between 6 and 12 depending on what and where i'm hauling. also run something with lubrication thru the system due to the low sulfur fuel.

 

The mileage you are getting isn't all that bad , i just made a round trip from san antonio to santa fe and back , pulling my 5er, going sa,to ft stockton 10.01 mpg ft stockton vaughn 11.02 mpg to santa fe and running around ,? as i didn't fillup till i left,return santafe to astoria 9.24 mpg to ft stockton9.30 mpg to kerville tx. 8.46 mpg < 70 + mph> my overall average was 10.494 mpg . 1805 mls. 172 gals. not what i wanted but considering all factors i am satisfied. cruise set at 65 mph except ft stockton, san antonio 70+mph. wife wanted to get home.

 

I have a trucking company and we have about 5-6 hotshots leased to us. All of them have 40 ft trailers.

2006- 12.5mpg......33000 combined weight
2003- 11.0mpg......33000 combined weight
2002- 10.5mpg......33000 combined weight
2005- 14.2mpg......33000 combined weight


we had 2 guys step up to single axles from 01 duallys, both were around 500,000. Get ready for injector pumps, transmission and rear ends...its coming, trust me....seen it alot

The rest of the company is flatbeds and stepdecks