Well, the 1st 1,300 mile trip, plus a couple of hundred local miles after the EGR cleaning and NO CEL. Low end torque and overall power was noticeably better. NO diesel additives this trip. Also, I have to say that my fuel mileage did go up a bit. Very happy about that!! Running empty @ a cruise controlled 75 m.p.h. the overhead was reading 16.5 m.p.g. up from the usual of 14.5 and the TRAX II fuel monitor was definitely in agreement. I have found that the overhead reads a little high at first but over a long distance will generally settle down to being very close to accurate. Again, I use the TRAX II for more accuracy as it is a digital monitor and I don't trust myself to fill the factory tank to the same level each fillup. Plus I'm not that patient either. That's 2 m.p.g. more than I was getting empty with the stuck EGR valve. Most importantly, towing mileage increased about 1.5 m.p.g. up from struggling to get just over 9 m.p.g. to a consistent 10.5 m.p.g. @ a cruise controlled 75 m.p.h. trailer weighed in @ 14k, minimal wind.
There may be hope for the 6.7 yet.

 

So I take it you had the Catlyst Full BS going on as well and took it in? Maybe you did something to have just the EGR cleaned?? Just wondering what the problem was and what the fix was and how it was fixed? Mine just took the dive last night i took it to the dealership with it saying 90% full. I had plenty of warning that it was coming as mine was made in March. Thanks

 

Never had the overhead say the catalyst was full or even near full. CEL & codes for the EGR valve stuck open was the problem. Started having the problem when the truck had about 27k miles on it. The fix was the dealer using an EGR Cleaning Kit to clean out the EGR pipe & valve housing. They told me they couldn't just replace the valve as it was a $700.00 part & restricted by STAR. Had to do the cleaning kit first as per STAR. Dodge tech said the EGR pipe was clogged with gummy gunk. Also advised me to quit using diesel fuel additive until the colder weather. Have posted about this before. They first gave me the updated flash but that did not correct the problem. I just wished that the EGR valve would've stuck SHUT and I would've left it that way instead of having to wait for someone to develop an EGR plug like for the Duramax's.
So far so good.

 

I agree with GMScott, my EGR was sticking open as well. Sure wish mine would have been stuck closed as well LOL...
At least I think I would. I really don't like what the oil looks like in my truck after just starting the motor after an oil change...

Mine was bought in March and I had never had a full regen cycle until yesterday when I finally got by my dealer and got the bootloader in and the new reflash. Then took the truck out with the star scan on and made it do a regen cycle.

We will soon see if this helps mine now.