Update on this issue:
I have been having a grey/light blue smoke problem sitting at a red light and taking off. After take off it will clear up. Wont smoke while in park. Only in gear at a red light. Pm'ed bowtiehatr about this issue and here is what he stated:

"what size exhaust do you have? i had a customer that hada 4 into 5 inch exhaust that would do pretty much the same thing. it was caused by the loss of backpressure due to the big pipe and the egr would flow off idle causing just enough turbo lag to cause the smoke. try disconnecting the egr valve and see if this is the case."
My response:

"Yes, i have a 5in turbo back. I basically bought it before i did research on here along with the cold air intake! Update and one last question if you dont mind. Dealer had it two days and service writer said they ran every test possible and test drove it and it didnt puff smoke and everything checked out normal. Drove it about 75 miles from the dealer and it puffed. My question is this. How did you come to the conclusion? What kind of test did you run to get the guys problem corrected? I told the service writer your scenerio and he said he would check it out, but who knows. Thanks for your time, Josh"

His response:

"basically it came down to experience. i had put egr and oil cooler on it for a white smoke concern and the turbo was cleaned as well. when the truck was hot it still would puff only taking off from a stop where the truck would have had to idle for at least 20 seconds and moderate pedal response was applied. it would smoke every time. i used ids to control the egr valve and held the egr valve shut and drove truck. no smoke. basically the processor was getting confused with the backpressure issue from the large exhaust and needing to run certain functions within the egr system, it would cause lag, overfuel for a split second, and puff of white smoke would be the result.

unplug your egr valve and see if the smoke goes away. if so, run a tuner that shuts off the egr system."

I have had the truck back to stock for two weeks now, but even with the tunes from the archive it would do this. Unplugged the egr valve today and as of now it hasnt smoked a bit! So i guess the egr is on for atleast the VXCF4 tunes. PUBLIC SHOUT OUT TO BOWTIEHATR, YOU'RE THE MAN

 

So now, does anyone want to trade a MBRP 4in cat back for a MBRP 5in catback?

 

yeah he's helped a me and a ton of people on this site. with how high tech these 6.0's can be it's great to have him around.

hahah maybe. i wonder if it would fit my cat-less 4" turbo back?

 

Only thing is i would miss the sound of how the 5in rumbles compared to the 4in. I personally can tell a difference.

 

It would fit. Mine was a cat back 5in before i bolted up the bigger down pipe and MBRP cat delete a year later.

 

i have always wanted a 5" for the sound. if i was closer by you i would probably be down but i'm in california so... plus it would suck if then i got the same problem as you but i think all my tunes are EGR off and i wanna delete that thing some day. but a 5" exhaust w/ 6" tip would look might nice on my truck. LOL

 

Thanks for all of the great info. Out of curiousity what specific tune (or tunes) of the VXCF4 strategy are you running.

 

Hybrid race, stock plus, and heavy tow

 

I tried the "General Economy" tune yesterday for the first time (first time ever loading a tune on a diesel). Scared the crap out of my wife when I punched it from a rolling start..she couldn't believe a big ole dually could move like that.

 

For some reason, my truck LOVES the stock plus. Dont know why, but i think it is the best overall tune to me for my truck. Dont know why. I suggest you try it

 

Thanks for the tip, I will try it today.

BTW, does it have less harsh shifts? The one thing I noticed was my shifts are way too firm for me with the General tune. Not sure if the trans needs to adapt or not.

 

Shifts are great with the stock plus too me