Carbon on injectors

[Paul1664]

Any ideas of what could cause this level of contamination?
Car has only done around 50000 miles.

Picture in attachment....

Garage originally thought (then dismissed) fuel contamination and don't have a current theory. They want to take the head off to investigate - all getting very expensive.

[lynns hubby]

Second from the left is the only one that would concern me, and that just looks like it was not sealing properly in the head and getting a bit of blow by. Looks like it needs the sealing surface at the bottom of the sleeve cleaning up and maybe carefully recutting if that's possible.

[Sotosound]

Originally Posted by Paul1664

Any ideas of what could cause this level of contamination?
Car has only done around 50000 miles.

Picture in attachment....

Garage originally thought (then dismissed) fuel contamination and don't have a current theory. They want to take the head off to investigate - all getting very expensive.

What vehicle of what year with what engine is it?