Had this happen in 2007. Covered under warranty, fortunately. What happens is some early model c7 heui pumps are bad, have a bad shaft,bearing. This pump pressurizes engine oil up to 4000 psi, which is then used to actuate the injectors at up to 28000 psi. When the heui pump goes bad it sends metal shavings down the passages in the head into the injectors. Repair is new pump, clean everything up, new injectors. Make damn sure you are using proper oil and oil, fuel filters are completely clean after repair.
It was 6k at the time if I recall. There's an updated pump and an after market solution but I don't remember the name.
Sorry
Cbig
