Help with ISX 15 CM 2250

[tree98]

Well for starters, how many miles are on it and has it been demandated? Have you pressure tested the egr cooler? https://youtu.be/T6yhOm1oiEc
Thats where I would start. You could also pressure test the head to find out if it is an injector cup. That injector cup repair your talking about isn't a guaranteed fix, in fact If I remember right it's basically a 50/50 shot but you definitely don't have to have the dealer do it and it wouldn't cost anywhere near that price they quoted you.