ISX15 Idling in farm operation

[tree98]

Rebuild that high pressure fuel pump now!!! Those things are famous for failing and taking the entire engine with it, meaning you can't even rebuild it because its so full of metal shavings. You're right at the mileage where the guts need to be replaced.
As far as the rest of it goes, get it demandated and don't look back. But have it done by someone HERE that knows what they are doing!! ie. MommaBurt, unilevers, Mr. Hagg