Ask if injector work has ever been done. I have an 06 used for pulling livestock. Injector went out at 150,000. Melted a piston and took out the turbo. I wanted to keep the truck so ended up putting a rebuilt longblock in, new turbo and injectors. Cost was close to 10 grand for this. I went with a machine shop out of NM. Very nice work on a rebuilt longblock, 3600 with core exchange shipped.
I talked with a few engine builders regarding this, they said the 24 valve is a great engine, but recommended changing injectors around 150,00, or putting on an aftermarket filtration system to filter fuel down below 8 microns to preserve injectors.
