04 6.0 LOSING POWER & SMOKING @ HWY SPEED

[JCF1970]

At highway speed the truck runs fine but if I come up behind another car and let up then try to speed back up the RPMs will not come back up and it will white smoke bad. I have to pull over then I can put it in park rev it a little and it will clear out and run fine after that. It don't do it all the time and only when its warmed up. Its not using any coolant or oil. I pulled the EGR and cleaned it and it did not help. The EGR was dirty but not stuck open. Do I need to replace the EGR or look somewere else. I took it to the dealership they said it never did it during their test drive they flashed the ECM and that did not do any good. I have own the truck since 60000 miles and it now has 125000 and the truck runs great until this happens and then it clears up. It may do it 5 or 6 times in a row or it might not do it for a couple of days. Since I have owned it I have always changed the oil and all filters ontime and had the cooling system flushed and coolant replaced at 110000 miles.
SOMEONE HELP PLEASE!!!!!!!!

[kingranch89]

im not to sure on this but im sure someone will come along that will be able to help soon.....subscribed