Sorry to hear about the hazing
It would be of interest to know more about the truckís history and mileage.
As you have probably learned through search, statistically VCO injectors in our LB7s seem to begin showing signs of failure (hazing or long crank times or both) at around a 70k cycle. YMMV, of course.
Also, search balance rates and you will learn they tell only part of the story on injector failure.
High return rates are typically caused by erosion of the ball and seat in the injectorís internal return circuit. Iíll let you explore that further on your own.
Finally, the dreaded ďhazing at idleĒ is most often an indication the injector nozzles are not sealing properly, allowing fuel to drip when they should be off. The accumulated, carbonized fuel on the tips gradually deteriorates the spray pattern and along with excess fueling, most notable at idle, causes the hazing. Above idle, the tiny amount of dripping fuel is largely inconsequential and owners can be frustrated because other than idle haze and some loss of mpg, the truck seems to be operating well. I tolerated that situation for months, till my wife became too embarrassed to ride in the truck.
Again, based upon the experience of many other owners Iíve read about here, I feel comfortable saying injector replacement is in your future and recommend you investigate SAC injectors as replacements. They were used in all Duramax following the LB7.
Keep in touch. A wealth of accumulated knowledge and experience here.