I have a 2001 Chevy Silverado, 2500 with the 6 liter engine with 86000 miles.
I had the ejectors flushed at at a local dealer to improve performance.
They flushed the system out and I changed the oil a day later.
My oil changing routean is every 3000 miles.
The 6 liter normal engine start-up noise goes away shortly after start up.
I have devolped a engine knock and have returned to the dealer twice.
The first suggestion they gave was that I used cheap oil was I change it again.
The second time I returned the dealer listened again and feels that some carbon loosened up from the flushing is in stuck in one of the cylinders.
They have instructed me to try to run it hard a couple of times and pass a few cars to try to blow it out.
If this will not work they feel they will try to locate the noise and remove the plug bring the piston to top dead center and try to flush it out.

What damage will I have if I run the truck for the next 5 days?
What is the right fix for the problem without removing the head to remove the carbon?
Not sure if the carbon came from the EGR valve when I it opened after the flush.
The noise is on the passenger side of the engine and is most noticable at 1000 rpm.